Using Mulch in my Greenhouses

On Facebook I see a lot of photos of people's greenhouse. Here in Hawaii, they are often actually high tunnels as opposed to the greenhouses one finds on the mainland. But regardless of what you call them, folks here use them to grow food. Sometimes plants are grown right in the ground, but more often than not, they are growing in some sort of raised bed or container because of our lava rock ground. What I've noticed is that no one seems to use mulch in their greenhouses. I'm not sure why.

I mulch the soil in my greenhouses, for the same reason I use mulch in my outdoor gardens. 

... Weed suppression

... Soil moisture retention

... Add to the soil fertility 

Due to the sun and heat, the soil inside the greenhouse dries out quickly. It's common for me to water a greenhouse every other day if it is not mulched. By mulching, I can reduce the need to water to about every 5th day. When it's not windy and sunny, the greenhouse can go a full week between waterings. 

I prefer to use fresh grass clippings for mulch, especially for the greenhouses. It's easy to use and easy to control the thickness of the mulch. 

Mulched basil and young tomato plants in a greenhouse. 

Why Mulch a Temporarily Unused Garden?

"S" emailed me and asked about why I bothered to mulch the soil in the greenhouse that isn't being used at the moment. She didn't see the sense of wasting the mulch or wasting my time. 

Actually "S", that's a great question. And by the way, you'll soon see that it isn't waste at all, at least not from the point of view that I'm coming from. 

Ok. First question to consider......why do I use mulch? 

1- to control weed regrowth

2- to retain soil moisture

3- to protect the soil microbes

4- to provide nutrients to the plants

5- to retain soil so that it doesn't erode or blow away

6- to feed the worms 

If you noticed, I applied water to the greenhouse soil prior to applying mulch. That's should give you a big hint. 

The soil in the greenhouse is fairly young. I'm in the process of building it up. In order to get a good soil ecology going, I've been using generous amounts of fresh compost, supplementing that with livestock manures and urine. To create a preferred environment for soil life, I've been keeping the soil moist and shaded. This has meant watering once or twice a week plus keeping the soil surface covered with mulch. If soil drys out or bakes, I'd be losing much of the soil microbes and other soil life (worms, springtails, etc). The soil life is what decomposes the compost and manure teas, thus eventually providing plant nutrients. It's actually a complex cycle, but basically that's what's going on. 

By covering the soil with mulch, even though I'm not presently growing a crop in the greenhouse, the soil life is preserved and is busily doing its thing. It's in somewhat of a holding pattern since there are no actively growing plant roots. But by being evenly moist and protected from sun, the soil life will do fine until I plant the next crop in the next week or so. The soil life will be able to re-establish their colonies and network, thus recovering from the light tilling by the time the seedlings start to grow. 

So "S", even though I'm not growing an edible crop, I am growing a vast colony of soil life. I utilize this soil life in place of commercial fertilizers. So having a thriving soil life community is extremely important to me. Even with an edible crop, I will tend the greenhouse soil, keeping it moist, shaded, and full of food for the soil life. 

Getting the Greenhouse Ready

Greenhouse #1  ---  The crop has been harvested, the crop residue and weeds removed. These went into the compost piles. So the greenhouse was empty, the soil bare. As most of you know by now, I don't like to have bare soil. So until I had time to revitalize the greenhouse, I covered the soil with a light layer of county mulch, enough to keep the soil completely covered. 

Now I'm getting the greenhouse ready for replanting. The next step was to top the beds with a 3 inch thick layer of compost and till it in. But before I tilled I checked the soil pH, which was too low. Not surprising because I'm working with fairly new soil. A dusting of wood ash plus a sprinkling of dolomite lime will help this. Then I tilled this into the top 4"-6".

After tilling, the next step was to moisten the soil. In fact, I watered it well at a rate of one gallon per square foot. This got the entire tilled layer wet, plus some of the sub layer. 

I've watered the left side (the soil looks darker). Next I'll water the other side. 

I'm not done. Next step-- mulch. Whipping out the lawnmower, I harvested 6 trashcanfuls of clippings. I used them all, well mulching this greenhouse. 

One side is mulched. I did the other one right after taking this photo. 

 Now it waits in readiness.

Greenhouse #1 Update

The cucumber/zucchini greenhouse is spent. This one is Greenhouse #1. Time to tear out the old plants, rejuvenate the soil, and plant again. I sowed the seeds for those plants on June 6th in the mini-greenhouses. They grew there as seedlings until they were transplanted to the large greenhouse on July 1st. On July 16th I harvested my first baby zucchini. The first cucumber was picked on July 29th. By August 25th the plants were starting to fail, so I removed the poor looking ones, keeping the healthiest of the group. Last week I finally called it quits. The plants looked terrible. They were over mature, brittle, had lost most of their leaves, and were no longer flowering. I kept them in the greenhouse just long enough to harvest the last of their fruits. 

Tired old plants ready to be pulled out. 

There were a total of 9 cucumber plants and 7 zucchini. From these I harvested 102 cucumbers and 41 zucchini. I find this to totally amazing because prior to this experiment I had produced only a few cucumbers and zero zucchini. All previous attempts had succumbed to pests and disease. 

Cleaning up the greenhouse, I pulled the plants, pulled or cut off all weeds, and found two humongous overly mature cucumbers hiding down along the bottom of the greenhouse covering. So they brought the cuke total to 104, although these two giants went to feed the chickens instead of us.

12" slicer cuke, and 6" pickler. 

I'm right now in the process of adding soil amendments, which I will lightly till in before replanting. A five gallon bucket of fresh sheep manure per garden bed (each bed is 50 square feet). A 3 inch deep layer of homemade compost. A good sprinkling of dolomite lime, because my soil is deficient in available calcium. 

Cleaned up and ready for soil amendments. Crusty, the black farm dog, is helping. 

The soil in this greenhouse is in the process of being improved and built up. The cukes and squash were the first crops from this soil. So I was impressed with the yield. Of the cukes, the Saber variety was by far the most productive. The other varieties suffered from the soil not being up to par. Of the zucchini, Desert far out did Golden Glory and Black Beauty. Again, I suspect the soil fertility is to blame.  I plan to retry all the various cucumber varieties again, and I'll grow Desert and Golden Glory again. But in place of Black Beauty, I plan to try Partenon zucchini instead. 

Greenhouse Update

I noticed a few dots of powdery mildew starting on the tomato plants in the greenhouse. Time to clean them up and do something about it. So I removed all affected leaves, thinned out the foliage on the bottom of the plants, removed a lot of spindly sucker branches, and removed some of the excess foliage jammed in the center of the plants. On the way I harvested a number of tomatoes. Plus I picked the sweet peppers that were ready for eating. Most of them are the mini peppers which appear to be earlier producing than the regular blocky types.

Lots of little peppers, 4 different varieties. Plus the two last cucumbers from this planting. 

What to try next on the powdery mildew? I've tried milk with little success. And various urine concoctions with limited success. I was going to experiment with compost teas, but I'm not prepared. So I went to the Ace Hardware store and bought some sulfur spray. With the sun not shining.....it's actually raining, yet again.....it was the perfect time to spray. Everything in that greenhouse got a nice shower in garden sulfur spray. We shall see what happens with tomatoes. The sulfur worked ok on the cukes. I plan on spraying once a week initially. 

A medley of tomatoes, plus some blue potatoes. Yes, blue! 

Checking in the other 2 greenhouses, I saw that they needed work. #1 needed to be completely cleaned out and redone. Removing the old cucumber plants, I found two cukes hiding....one fat green one and one white one. Ah-ha, cucumber salad with dinner tonight! I wasn't expecting to get anymore cukes. Anyway, I got this greenhouse cleaned out. Over the next couple days I'll drag in some bags of compost and till it in, refreshing the beds. I'll also add some dolomite lime, since I know from experience that my soil is deficient. (The tomatoes told me so with blossom end rot showing up on a few of the fruits.)

#2 still has lima beans growing, but things are going downhill. The Succotash variety is pau, so I removed them all plus their string supports. The Dixie Speckled Butterpea and Jacksons Wonder look to have one more picking left to go. By next week I'll pull them all out. But on the opposite bed, the Hawaiian  black & white landrace is just getting going. So of course I'll be letting them stay. 

One thing I discovered that is pretty cool. The Dixie Speckled Butterpea is sending up a second flush of flowers! I wasn't expecting that. Neither Succotash nor Jacksons Wonder produced more flowers. So it appears that with Dixie, I could manage the plants for a second crop. Interesting. These particular plants haven't been managed correctly for me to do this. They have sprawled every direction and flopped out into the walkway. So I will be pulling them out and starting over again. But this time I'll keep in mind that they might be producing a second flush of flowers. 

Last thing of the day, go check on the potato boxes. Blue Adirondack was ready to harvest. I got 4 pounds of tubers from only 1 pound of seed spuds. Not bad considering how wet it's been lately. 

Greenhouse Yield by the Dollar

To date I've gotten 59 zucchini. Around here, zucchini sells for $1 each. 

So far I've harvested 56 nice cucumbers. These also sell for $1 each at our farmers market. 

I've never seen fresh lima beans for sale here, so I don't know what their monetary value is. But I think I could get $1 for a sandwich baggie unshelled if I sold them. So I'll guess the limas to date could be valued at $10, and I've only harvested about 1/4 of the anticipated crop. 

Large tomatoes sell for $1 each. 4 medium ones for $3. Cherry tomatoes $3-$5 a sandwich baggie, depending upon the color and shape. I haven't the foggiest idea how many tomatoes I will be harvesting, so I'll skip adding their value into the total for now. 

Same for peppers. I can't add their value because I don't know how many I'll get. I've harvest 22 skinny frying peppers so far, but the main bulk will be the blocky types, which aren't ready yet. 

So let's see........

...zucchini -- $59

...cucumbers -- $56

...lima beans -- $40 

...tomatoes & peppers unknown

That's $155 so far if I had simply sold those veggies. Thats $155 for the first 3 months counting just 3 crops. I'm a long way from determining how long it will take for the greenhouses to financially break even, then turn a profit. But regardless, I'm quite pleased with this experiment so far. 

I have a feeling that those tomatoes, if all goes well, will be paying for the greenhouses. 

Greenhouse Update

Zucchini squash.....

      Growing zucchini in a protected greenhouse actually works for me. Wow. Pickleworm has been the number one problem before, and the screened greenhouse solved that by blocking the moth. Powdery mildew was the other crop destroyer, but spraying the foliage with a sulfur spray controlled it. Being in a greenhouse meant that the sulfur didn't get washed off by rain, so it was very effective in preventing mildew. And squash borer also couldn't get past the screening to destroy the plants. 

     I tried 3 varieties and found one that far out preformed the other two. "Desert" produced and grew the best. I plan to try another variety with parthenocarpic traits and see how it compares to Desert. 

     I initially planted the seedlings too close together. Over time the plants trailed, developing 2 1/2 to 3 foot stems, interfering with one another and making it difficult to harvest and care for them. Plus I planted them all at the same time, rather than spacing the timing out. So in the future I plan to plant two seedlings, wait a month and plant two more, and repeat. The goal will be to have a total of 6 zucchini plants producing on different time schedules. I know this could work during the summer half of the year here. We shall see if this plan works during the winter half. If it does work, then I potentially could have a supply of zucchini for our table year around. 

     This experiment yielded 57 zucchini. Plus I still have one plant still producing, with three little squashes soon to be ready for picking. 

Cucumbers.....

     I've learned that growing greenhouse cukes could work on my farm, but I need to dramatically improve the growing conditions. I need to learn more. Some of the varieties I tried did better than others, and only one did really good. But I suspect that's because I don't have the soil and nutrients right for cukes. And I don't have the watering timed well enough. Powdery mildew became a problem before I got a handle on it, thus it effected the plants. 

     All the varieties I tried were worthy of growing, so I don't plan to discard any of the leftover seed. I'll grow them all again. 

     This experiment yielded 53 cucumbers and I kept the Saber variety plants, thus I'll be getting more for the next week or two. But the plants are looking old, so I don't know how long they will hang in there. And as I said, I don't have the growing conditions right yet. 

Tomatoes.....

     All the tomatoes are doing great in the greenhouse. And I'm just now starting to get large tomatoes. So I'd deem this a total success. I might be picking my first tomato next week. 

Peppers.....

     Just as with the tomatoes, the peppers are doing very well. The plants are a lot taller than when grown out in the main garden, which may have to do with reduce light intensity. They are just starting to produce peppers, so it looks successful. Being that the plants are tall, I may need to provide some support stakes for them when the peppers start developing. The weight may cause the plants to lean. 

Lima beans.....

     Since I've been harvesting lima beans, I declare this experiment a success.  It's the first time I've been able to harvest enough limas to eat. The next step in this experiment will be to test varieties, to find ones that do better than others and that I like to grow. 

     Succotash variety produced earlier than the others, but it is not nearly as productive in the long run. The vines appear to have stopped growing now. I can't say that for certain yet, but I'm not seeing fresh new growth. Being that it isn't very productive this first time trying it, I'm thinking I need to give it a second chance. Perhaps the soil isn't quite right. I like the colorful beans, but I find a lot of duds in the pods. I don't know if this a variety trait or a deficit in the growing conditions. I'll try growing this again to see how it does the second time around. 

     Dixie Speckled Butterpea is a winner! It's growing well and producing tons of limas. It's easier to shell than Succotash and doesn't have the problem with duds in the pods. It's out producing Succotash by a mile. I'll definitely grow this one on a regular basis.

    Jackson Wonder - the verdict is still out. The plants are growing well but it is a later bloomer than the others. Time will tell if it can produce under these greenhouse conditions. 

     Yield to date is 3 1/2 cupfuls of shelled beans. I'm thrilled just by the fact that I'm getting my our homegrown limas to eat. I'll be getting a lot more because the Dixie Speckled Butterpea plants are still loaded with pods. So are the Jackson Wonder beans, although I can't confirm yet that there are maturing beans in those pods. 

Watering The Greenhouses

Several folks have asked about how I'm watering in the greenhouses. I'm using a rather low tech approach......a hose. 

Ok, it's not completely simple, like turning on the outdoor faucet and letting the water do its thing. The greenhouses are about 500 feet from the nearest water faucet. Plus the house pump is small, not strong enough to drive the water that far. Nor do I have 500 foot of hose just lying around not being used. So I do something a bit different. 

Right now I'm using the truck to transport water in trashcans down to the greenhouse area. Then using the portable generator, I use an electric sump pump to apply the water via hose. This works, but it takes time. 

While there are lots of cons to this method, there are a couple pros. 1- I can add a liquid nutrient to the water to provide the plants with a fertilizer boost. 2- I can apply the water directly to the soil, thus keeping the foliage dry. 3- rather than "one size fits all" watering, I can apply extra water to spots that need it.

I figure that in the future I'll develop a better method. Not sure at this point what I'll do. Water storage directly in the greenhouse area? Some sort of gravity feed drip irrigation? 

Before y'all run it and start doing all your garden watering with a hand held hose, be aware that almost all gardeners severely underwater their plants when using a hose. People think a lot more water gets into the ground than it does in truth. The easiest way to check is to use a finger to scratch the soil when your done. Visually check to see how far down the soil is wet. Your results may surprise you. In my case I know that I'm applying 100 gallons to a 100 square foot garden bed. So that's 1 gallon per square foot. I've already tested the soil and found that it wets the soil deep enough to satisfy both me and the plants. 

One more note...... I never let the soil completely dry out. I apply water while it is still a bit moist. The reason being, dry soil on my farm is very difficult to re-wet. The water runs through it in channels, leaving behind 95% dry soil. If the soil is damp, then it takes the water with no problem. 

Observations on my Greenhouse Experiment

I've only had the greenhouses operating full scale for the past two months. But already I've been able to make several observations. 

..... Covering. Plastic film vs greenhouse tarp. The plastic film allows more light into the greenhouse than the tarp. But the plants don't seem to be having severe problems with that. I have zucchini, cucumbers, tomatoes, peppers, eggplant, and lima beans growing and none seem slow growing or stunted in any way. None appear to be abnormally stretching, trying for more sunlight. But then, tropical sun is quite intense here. Apparently enough sunlight is getting through the tarp. 

       The tarp is definitely a lot stronger and tear resistant compared to 6 mil poly film. I accidently dropped a 2x4 against the tarp and there was no damage that I could detect. Wonderful! 

..... The veggies I opted to grow are growing faster and larger than they did when I grew them in my standard garden plots. I'm guessing that the higher daytime temperature and protection from wind contribute to that. High humidity is normal here, but it is probably higher inside the greenhouses. 

..... Less pest problems. I'm finding a few grasshoppers that managed to sneak in, but not much else. Most importantly, no pickleworm moths! 

..... Watering. Since rain can't water the plants for me, I need to provide the water that they need. By trial and error, I've determined that each greenhouse needs close to 100 gallons of water weekly. 

..... Lima beans. The limas look great! Best I've ever grown. The extra heat seems to suit them just fine. And I'm seeing lots of pods that appear to be developing beans inside them. Time will tell if I actually get a crop of lima beans.  

..... Cucumbers. I'm growing only parthenocarpic greenhouse varieties. Some are doing better for me than others, though all have produced some cukes. The best ones so far are Saber, Nokya, and Socrates. 

..... Zucchini. In the past I've never been able to produce a single harvestable zucchini. To date I've harvested 28. Yes, 28. Yikes! I'd call that a success. I'm trying 3 varieties : Desert, Golden Glory, Black Beauty. Desert has been doing fantastic. Golden Glory is so-so. Black Beauty isn't worth growing again. Initially I let nature take its course, and without much fuss, the plants produced some zucchini. But as the plants aged, I saw more aborting. So these past 10 days I've been hand pollinating, resulting in more squash consistently setting on the plants. 

..... Powdery mildew. This is a real common problem where I am, so I've been expecting it to rear its ugly head. It's been 2 months since I started this experiment, and I'm just now seeing some powdery mildew on the zucchini. I haven't done anything to try to prevent it because I wanted to see what would happen and what I would be up against. And I needed a baseline to work from in order to develop some prevention methods that actually work. Plus I wanted to know which varieties had the best resistance to it. 

      Now that I'm seeing powdery mildew, I'm instantly removing any leaf that shows the beginning dots. This will only forestall the inevitable, but should allow me to harvest some more squash before the plants succumb. I haven't seen mildew on the cucumbers yet, but I fully expect to see it soon. 

Bracing for a Hurricane

Hawaii just had a hurricane pass south of the islands -- Hurricane Erick. With all the storm warnings, I did indeed take a few precautions. I filled the truck up with gas, plus I refilled all our gasoline storage cans. And other than bracing the greenhouses, that was it. We already keep plenty of drinking water and food on hand. Our in-house pharmacy is well stocked. We always keep extra propane on hand. And there's plenty of ammo in case I'd have to dispatch any injured livestock. The generator and chainsaw are always kept in repair. So I think we're covered.

Bracing the greenhouses is the only unusual step I take. Not that this simple method would be adequate for really high winds, but it's fine for the storms that usually hit us. I discovered from previous storms that the central hoop of the greenhouse is the weak point. So if I install a single cross brace, it saves the hoop from being overly torqued and thus breaking, 

Cross braces installed. 

I guess I could make this more complicated, but this set up works. It's easy and quick to install and take down. And it only requires two 2x4s, two metal spikes, and a few screws.

The metal stake is one used for concrete forms. It has holes th can put a screw through. 

As I've said, this is only a solution for a small hurricane. Perhaps I should work on a more substantial solution in the event of a stronger storm. 

Greenhouses Ready for Planting

Because of heavy winds we got a while back, all three greenhouses needed some repair. The oldest one had a few broken hoops. The pcv pipes snapped because then had become brittle. It was to be expected, and I wasn't surprised because I had gotten so many years of use out of them. The building of that greenhouse had been their third project. Yup, I re-use materials when possible. The other two greenhouses had pipes that were fine, but they both needed new screened end walls (Bucky the goat torn up the screens one day when he got loose.) 

Replacing the broken pipes was a quick and simple job. Unscrew the old ones, screw in the replacements. With a battery powered drill, removing and putting in screws is a snap. 

The poly cover on the broken greenhouse had torn in several places due to the jagged pipe ends. Since I needed to recover it, I took this opportunity to try out something different : a greenhouse tarp. Instead of being poly film, it's just what it sounds like --- a finished tarp complete with grommets. I opted for the kind with embedded mesh, hoping it will be able to withstand the winds better. It lets in less light, but since our tropical sun is intense, that may be a benefit. We shall see. 

The ground beds needed some TLC. I first removed all the weeds.

Because of disuse, weeds invaded the greenhouses. 

Next I added an inch of sheep manure. Then 3 inches of county mulch. After a good watering and allowing it to set overnight, I dragged out the tiller and rototilled it all in. A second watering, then a covering to protect the soil. 

I used old sheets to protect the soil until it's time to sow seeds. 

In this case I used old sheets in one greenhouse. They will help retain soil moisture until I get it seeded with the hot weather crops (okra, lima beans). In the other two greenhouses I used just county mulch, about 6 inches deep (it will settle to 2"-3"). I'll be transplanting larger seedlings -- tomatoes, peppers, squash, cucumbers, so the mulch won't be a problem like it would be for seeds. 

once the mulch was applied, I gave the beds a good watering.  

Getting water to the greenhouses is an issue that I haven't fully resolved. Right now I'm storing water in trashcans. I'll use the sump pump & generator to water the greenhouses as needed. To fill those trashcans I need to bring water over from the ag catchment tank, or transport it from the county taps (via a tank in the back of the pickup truck). Not the best solution. Perhaps later this year I'll set up a catchment system beside the greenhouses, but I don't have time for that right now. If the water issue gets to be annoying, it will prompt me to take action sooner than later. 

Greenhouse Back Online

I'm covering my greenhouses in greenhouse plastic. As you recall, I initially used off-the-shelf, run of the mill poly plastic, but it is not UV protected. So it lasted less that a year.  After looking around, I found a source for greenhouse poly who would ship it to Hawaii at a reasonable cost. I bought 4 rolls. In hindsight, I should have ordered 6. Oh well. 

The first greenhouse is now recovered. Without much hesitation, I went about adding fresh compost to the beds and lightly tilled it in. 

All these bags were half filled with compost, so I used quite a lot. Why? The beds inside this greenhouse only had a few inches of soil, so I needed to add volume. 

After tilling, it didn't take me long to drag out the veggie seeds. The little blue sticks indicate where I planted them so that I will know where to target the watering hose. 

This house will be growing cucumbers, tomatoes, and zucchini squash. Both the Dukes and the squash are parthenocarpic. Tomatoes self pollinate. If you recall, I have the ends of the greenhouse screened. This is designed to exclude the pickle worm moth and fruit flies. Thus I'm going with veggie varieties that I don't need to hand pollinate myself. 

ps- 12-22-17 greenhouse #2 got covered in be greenhouse poly

Back To Work

Oh no....it's not me that I'm referring to (as you gather by now, I seldom stop.)  It's my mini greenhouses. They've been idle for some time, awaiting new plastic covers. Now that they're back in shape, they are also back in service, Two weeks of using whatever spare time I could scrap together, and now I have 8 of the mini greenhouses back in production. 6 of them are holding freshly seeded trays........

Cabbage, Chinese cabbage, broccoli, kale, onion, leek, radish, lettuces, spinach, Asian greens, bok choy, cilantro, dill, basil, beets. The first seeding was on the 6th. The next was on the 12th. And I just seeded a bit more yesterday. Some of the seeds have sprouted and I've transplanted to little seedlings into growing trays or individual pots already. 

Above, newly transplanted seedlings. I transplant them as soon as the develop substantial cotyledons. So far two of the mini greenhouses are holding little transplants. Chinese cabbage. Cabbage. Broccoli. Bok choy. Radish. Kale. Lettuces. Within the next two weeks these houses will be busting with seedlings. I'm planning on getting at least 16 of them full by the end of the year, hopefully more. 

Many of the seedlings will stay put to grow in the mini greenhouses up to harvest time. Lettuces and other things being grown for young salad greens: kale, spinach, Asian greens, bok choy, tatsoi, radish, lettuces. These mini greenhouses are protected from slugs, and with the danger of rat-lung disease, I feel it's important to grow salad and raw foods slug-free. While some places in Hawaii are very low or non-existent slug populations, that surely isn't this farm. Slugs are common here. 

The seedlings that are in individual pots or plant cells are destined to either the garden or for sale at the farmers market. . 

Attaching Greenhouse Plastic in the Mini Greenhouse

"D" wrote to say....."Hi Su,
I am in Honomu and your mini greenhouse is EXACTLY what I need.
Would you please let me know what you used as clips to hold the plastic to the PVC?
A post on your construction method would be great too...."

I tend to keep things simple and cheap. So I use an old worn out garden hose. Using a pruning shears, I cut 3" long pieces. Then using the shears, I cut I slit the full length of the piece. 

I don't bother to drill a hole for the attachment screw. The above pieces are being reused, thus the reason you see a hole in them. 

I guess you could use just about any kind of screw, but I had these little screws with wide heads. I tend to use whatever I have on hand, get for free, or pick up cheaply at thrift stores or yard sakes, 

 

I use screws instead of nails because they are easy to punch right through the hose and pcv without pre drilling a hole, plus they grip well. 

I apply the greenhouse plastic, then slip a piece of hose over the plastic and over the pipe. Then drill the screw in. I use one of the battery operated drills because I'm working in a spot with no electricity. 

I've had a couple of episodes of quite strong winds and the plastic stays in place. I have the mini greenhouses oriented so that the prevailing wind blows through the tunnel, not against it. Thus I haven't had any problems with the greenhouses blowing over. 

As for the construction, again, I keep it simple. So simple that it drives hubby nuts. He would make them far more substantial. I simply nail two 2x4s to each corner of a pallet for each leg. The two pieces are first nailed together in an "L" configuration then nailed to the pallet. It's not real strong, but I'm not moving the pallets around, so it's stable enough. These are just quick and easy legs. 

Then I bend the 1/2" pcv pipe and screw each end to each corner, one pipe per side of the pallet. I think I used 8' or 9' pipes. But any length would do depending upon high tall you want the arch. For stability, at the top I screwed a top cross bar, connecting the two pipes at the top of the arch. I used pcv so that this brace would be smooth and not tear the plastic. Then for more stability I added four braces (two each side of the pallet table top) going from the middle of one pallet side up to the pcv pipe before I got too far along in its arch. I used guava sticks.....for a few reasons. Guava is free. The sticks are fairly smooth so as not to tear the plastic. Guava is fairly durable. It's easy to work with. So now the pcv arch is fairly stable and ready for plastic. I painted to wood because it made hubby happy. 

The cost was low. For most of the mini greenhouses I used free, reused materials, or things I had in hand. For the last few I had to buy the pcv pipe. 

Mini Greenhouse Fixes

My Initial experiment with the mini greenhouses were a success. My hubby saw them as failures because....

....the plastic shredded 

....the ground cloths became slug motels 

Those two problems just need tweeking. Since I plan to keep using these mini greenhouses, I'm upgrading to greenhouse plastic. Greenhouse plastic is thicker, stronger, and UV resistant. Between the winds here and the tropical sun, I don't expect to get 10 years out of it, but if I can get several years I'll be happy enough. 

Covering the ground was good for weed control, but bad for dealing with slugs. When I pulled back the ground cloth just to check out of curiosity, YIKES! It was a slug haven. They must have been having weekly orgys because there were slug eggs here, there, everywhere. Hundreds, no thousands, of slugs. Ok, the ground cover was a real bad idea. It allowed water to drain through it and create a nice dark, moist environment. So it had to go. I'd rather deal with weeds. 

Recovering the mini greenhouses wasn't difficult, it just took time. Lots of backing out screws then re-screwing in order to reattach plastic sheeting. Working at a good clip, it took me 20 minutes to do each mini greenhouse. 

At-da! Job done. Ready for replanting. 

First Greenhouse Crops

I've been real eager to get something growing in my new greenhouses. But alas, I haven't finished filling the growing boxes with dirt. But I've started at least.

I've been mining dirt specifically for this project. To the mined dirt I've added 25% compost and mixed it in. That's quite a bit, but the mined dirt doesn't look very fertile. I'm hoping that this ratio of compost to soil will work. Time will tell. 

Above -just planted

I've filled about 6' of the new bed. My planting fingers got itchy, so I planted 6 cucumbers and 10 patio tomato plants. Yeah, I'm pushing it. But boy does it feel good seeing something green in the greenhouse. 

I figure that the cucumbers can be a vertical crop, trellised up the sides of the greenhouse. The tomatoes will be a horizontal crop, spreading out to cover the soil. That's the plan at least. 

Above -ten days later 

My first baby cuke! 

Over the next week or two I'll keep mixing soil and adding plants. 

Simple Greenhouses - Update

So here's where I last posted ......... 

Basic greenhouse structure is up. Next step -- build some raised beds. Why? Because the greenhouses are on a pahoehoe shelf (pretty much solid lava rock). There's less than an inch of soil in most spots. I'm making very simple raised beds, 12" deep, out of scrape and recycled plywood. 

Very, very simply constructed. I'm not looking for something that will last years. 

Before adding dirt, I lined the bottom with layers of cardboard to help deter the grass. 

Next, I started filling in with dirt that I harvested from on my own farm. 

Oops. I forgot to cover the plywood with some old black trash bags. I think that keeping the soil off the wood might make it last longer. That's the idea, at least. Luckily I hadn't put much dirt in yet. Then I went back to filling the bed. 

Another quick and simple thing, I temporarily secured the plastic with clothes pins. Once the box is filled and the soil prepared & ready for planting, I'll remove the clothes pins and tack the plastic edges down using a staple gun. 

Once I have the boxes 3/4 filled, I plan to add a goodly amount of compost and some horse & rabbit manure, and till it all before I plant something. Each box needs quite a bit of dirt to fill it, so it's going to take me awhile. 

Last tasks.....besides the soil......is to screen in the ends (to keep out fruit fly and pickleworm moth) and attach some sort of trellis to the greenhouse walls. 

The doorway is really simple for now, just draped screening that I can tie down to an upright 1x4. . Eventually I'll make a more substantial door. 

And in the above photo, and the one two more up, you can see that horizontal bamboo poles have been attached to the inside of the greenhouse. I figure I can tie string or attach some sort of trellis system to them. By the way, the bamboo grows right beside the greenhouses and can be seen rising above the house in the photo above. How conveniently located! Just dumb luck. 

Simple Greenhouses

I'm on a roll! With the completion of 22 table top mini greenhouses (I still have two more to make as soon as I find a couple more pallets in good shape), I decided that I also want larger greenhouses in order to grow protected veggies. Things like slicing tomatoes, cucumbers, zucchini squash. The plan calls for screening to keep fruit flies and pickleworm moths out. Here's what I have so far....

I've actually made two of them now, with two more in the plans. The one pictured above is located in 100% shade, thus it will be used for storage and a work table. The ends will be left open. 

I put an overhead ridge pole in for stability, and used some scrap pieces of pipe for bracing the side walls. 

I used long screws to secure the pieces to each other, and used the old garden hose pieces to attach the poly sheeting to the frame. Putting on the plastic sheeting was by far the most difficult part of the job. 

The plastic hoops were attached to the inside of the ground framing. This means that they push against the wood so that they won't pull away, like they might if attached to the outside of the framing wood. 

I purposely laid the 2x4s down flat because when they are upright, I discovered that I tend to trip over them. 

Though I forget to take a picture, I secured each of the four corners with a t-post pounded into the ground, with the pipe hoops and 2x4 framing wired to each t-post. Hopefully this will be strong enough to keep the wind from lifting the greenhouse, causing it to blow away. Today we got some gusty Kona winds, giving the greenhouses a test. So far things look ok. 

The second greenhouse is in a sunny location. This one will be used for slicing tomatoes. I plan to screen both of the ends of the greenhouse to keep fruit flies out. I'm not sure exactly how I'll do that, so I'll have to let you know when that happens. 

Mini Greenhouse Tables

The blog has been quiet lately while I've been working on a project to grow fresh greens (lettuce, spinach, arugula, etc). The problems I'm trying to overcome are slugs and turkeys. Slugs not only eat holes in the leaves, but contaminate them with slime. We have rat-lung disease in this island, and slug slime can pass the parasite. And of course, turkeys can eat the entire crop in less than a hour. 

For the slugs, I've tried hand picking, using ducks, using traps, and spreading around slug bait. While all these help keep the numbers down, I still get slugs. But when it comes to safely eating fresh greens, I need to have zero slugs. So far the only zero slug environment has been achieved via protected hydroponics. I don't have a hydroponic system at the moment, but I might go back to a small one in the future, or maybe an aquaponic system. Right now I don't have the time to devote to it. Aaaaah, a future project! 

I figure I need to create something the slugs have a hard time accessing, or is easy to exclude them in some way. Plus a way to also confound the turkeys at the same time. What I'm building for my fresh greens could also be used for other crops. But I'm going to start out with lettuce, spinach, arugula, and other fresh greens. You know....the stuff that gets eaten raw. 

Ok......take wood pallets, some repurposed 2x4s, salvaged 1/2" plastic pipe, a worn out garden hose, and a donated roll of poly plastic sheeting. I have old paint (every color mixed together... it comes out a funky rosy grey) on hand for projects like this. I sprung for a new box of nails and a box of screws. Yes, you could use new stuff, but I'm opting to re-use when I can...low input/low impact farming. But in the end I wound up buying a few more pipes and a roll of plastic sheeting to finish off the last of the tables. 

I used 24" long pieces of 2x4s to put legs onto the wood pallets. Much of the time the tables were stable enough, but for the shaky ones I added bracing. 

Next I painted them. Just because it will look better in the end if they are all the same color. 

Took the pipe and cut it into 10' lengths. I could have used longer or shorter lengths, but the pieces I had lent themselves well to 10'. Drilled holes in the ends for the nails as they got nailed to the pallets. They're fairly shaky, so I attached a top rail (with screws) to connect the two hoops together. Then bracing was added (guava saplings cut to length) and screwed into place. Now the hoops were pretty stable. 

Attaching the poly plastic sheeting was a challenge. It was just difficult to work with with the lovely dang tropical breezes. It took a lot of patience and a bit of cussing. Short pieces of the old garden hose holds the plastic to the hoop. Just slice the hose so that it opened up and wrapped snugly to the pipe hoop. All that's needed is one screw to hold it in place. 

A short piece of scrap wood nailed over the plastic holds it to the pallet. 

That's basically it. I leveled up the table by propping a rock or piece of wood scrap under the legs. 

What's under the tables? Depending upon the spot, either worn out tarps or/and well used drop cloths. I have access to old linens which are handed out to people who need them, but some are too worn or stained for people to want. These get added to my drop cloth collection. 

So far I have 16 of these built. Perhaps I'll add a few more. We'll see. 

Next I'll show you what I'm growing in these mini greenhouses and how I'm doing it.