My version of a commercially available grow box. I have a real one, a gift, the produced a ton of tomatoes over the last two years, but at $50+, I can't buy too many in good conscience (at that price), when I could just go to the farmer's market and buy the tomatoes. So, I tried the less expensive route. Other than the weed barrier, this was $5 for the bin, $5 for the rocks and $2.50 for the dirt. I suppose $.05 for the watering device, too, but your mileage may vary on that (10 cents in Michigan, for instance).
UPDATES, some of which prove those who post comments are pretty darn smart:
I saw 25' of weed barrier for $7 at our local OSH; if you spread this over 7 bins (a good estimate), it's $1/bin, bringing the total to under $15, including the tomato plants.
The clear bins DO promote some algae. The real one I have (green exterior) just got dumped out, checked and cleaned and has no algae in it. My recommendation - go with something other than clear if you can find plastic you trust.
If you drill or cut holes for the top, make them bigger than you think they should be. I had plants rub against the cuts, and, well: cut plants. So, I have put some paper around the surviving plants (the plants are too big to take out to re-cut the lid). I'm trying to reseed in some of the holes, which should be interesting.
Step 1: Box and Water Layer
It strikes me this is the only unique step in my instructable. I took a box (3/$15 at Costco), and put "Lava Rocks for Landscaping" in as the bottom layer. Note the corner where the rocks do not cover the bottom -- this will be for wick. There is another corner in the front for water.
Step 2: Dirt Holding Layer
Mark where you want the drain hole(s) and drill. I use 2 or 3, as I drill them with a small bit, around 3/8".
Step 3: Keep Soil and Water Separate
This is the semi-unique step. Instead of the box top (clever), another bin (pretty good, but expensive), I used some weed barrier I had in the garage. It is supposed to keep weeds down but allows water through. If I needed to buy it, it was about $15 for 100 feet, according to the tag I found on it. Cut to about twice the size of the bottom of the bin. Place in bin, fold corners and put some dirt on to hold it into place. MAKE SURE YOU READ THE NEXT STEP before actually doing this, as these two steps go together.
Step 4: Water Supply
Cut the bottom off a plastic water bottle. If you're willing to drink from it, it should be OK to use here. Remove cap, place nozzle in the corner (remember where you didn't have rock), push down, put some dirt to hold in place.
This is a half litre bottle from Costco someone tossed at work. I have also used the skinny ones, but I had to get 2 pushed together. To do that, I cut about a half an inch off the bottom of one, then carefully pushed the neck of the second one into the bottom of the first. The ridges mated and I had a longer water spout. I wanted to use one from TJ's organic ketchup, but I couldn't get the label off for love or money (soaked in water for 3 days). Some helpful souls have given suggestions (see the comments), but I'm still striking out--I have a 2 year old ketchup bottle in the garage right now. That failure still annoys me, as the bottle is a good length and otherwise demands little real estate.
Step 5: Fill With Dirt
Now you have the box stabilized. Hint: move it to where you want it before you completely fill with dirt--it's heavy.
Add dirt, pat down, add some water to help compact, repeat until you have the dirt level where you want it. I used store-bought dirt, some "castings" from my worm bin, a touch of compost, and some lousy dirt from the lousy soil here.
I added fertilizer right after this photo. It seems to me the two big secrets of these bins are water control -- lots of water without root rot -- and lots of fertilizer, which gives the organic part of me the creeps, so I use less. The small secret appears to be the lid to keep evaporation, weeds & intrusions down.
I do not have a great idea for the top -- I was thinking of cutting a few large holes in the lid, and putting a garbage bag across the bin, snapping the lid on, and putting the plants in place through cut Xs in the plastic bag. Just using the lid might work (but creates a permanent pattern). Or, I may leave it open and deal with the evaporation--see my comments on the wine barrel on the next page.
Tomatoes, pole beans and peppers are on the agenda.
Step 6: Wait for Growth
I'm waiting for my seedlings to go in.
Also, I did this with a wine barrel (you might see it in the background of the rock shot) last year. I didn't do anything about a "top," as it was decorative and looked great with flowers, chive, one garlic clove and beans. Over the winter (Northern CA), we had marigolds from seed November - March (still there, for about 18 months until the lawn mowing guy tore them out).
Next up, I need a trellis for the beans. This may be a couple of 2x3s and some of the wire "fabric" they use to reinforce concrete. I hear they do great holding up tomatoes, too. Or it could be string, like last year.
Some Updates: Mixed results on tomatoes, but I liked it. Beans didn't do as well -- maybe they had too much need for water.