I used two cups of 10-10-10 cheap fertilizer. Lay it in a two inch wide strip away from the plants on top of the potting mix, they find it. Cover (so rain water doesn't get at the fertilizer strip and blocks weeds) and all you do is keep the reservoir topped off with water for the season. The theory is the plant gets the same water and food intake consistently while growing. For storage, I just pull the plant and leave in place. Leave mine out all winter, doesn't seem to bother them.
The photos of the buckets with seedlings are actually original Earthboxes some gave me. Mine are a DIY version of them, like mine better they hold more water and potting mix.
To refresh them in the beginning of the season, I just pull out about a 3rd of the potting mix and mix it with two cups of powdered lime, fluff up the rest (pull out any larger roots) add the mixed 3rd back in, add the fertilizer strip and cover. Ready to go again.
A bunch of us over at the Gardenweb we trying to make our own and this was my version.
Here's some instructions I did a while back to make them.
DIY Earthbox Photos
DIY Earthboxes, self watering planters. There are a lot of variations of these, so I've included some basic instructions showing how I made mine. These boxes hold 2.5cf of potting mix and 4 gal of water.
Materials to make 3 planters: Cost:
- 3 - 18 gal. storage box w/cover. $12
- 1 - 10' x 4" PVC drain pipe. $5
- 1 - 2' x 4' plastic egg crate light panel $10
- 1 - 5' x 1 1/2" PVC pipe $3
- 3 - 24" x 20" fiberglass screen material $1
- 36 - nylon ties $3
The storage boxes are Sterlite brand, purchased at Walmart. The smallest roll of fiberglass screen I could find at HD was 24"x100' ($27), there is enough for 60 boxes. You may have to buy a 10' length of 1 1/2" PVC pipe, will make fill tubes for 6 boxes ($6).
Cut 6 - 6" pieces out of the 4" PVC drain pipe (I used a miter saw). Drill 9 - 1/2" holes (I use a wood bit) in the tubes and stagger the holes 3 top, 3 middle, 3 bottom. Drill 2 - 1/4" holes at the very top of each tube, opposite sides, these are for securing to the screen. Snip the egg crate panel 18" x 15" (this will vary depending on the dimensions of your box). If your box has rounded corners, then snip out the corners to match. You should be able to get 3 screens per panel. Use two nylon ties to attach each tube to the egg crate screen. The egg crate panel seems flimsy, but it is very easy to snip out and saves you from drilling out the cover to make a screen. Once the supports are under it, it is plenty strong enough and provides great aeration.
Snip out the egg crate material from the middle of two outside tubes, they should be on the same side of the screen. Make sure to leave some edge squares intact so the screen is still supported by the edge of the tube. These are going to be the wicking chambers. On the same side, snip a 3 square by 4 square hole above the center tube, this is where the filler tube will go. (See photo below)
Take a piece of the fiberglass screen material and wrap it over the top of the egg crate screen, this will prevent the potting mix from falling through the holes. You can just hold it in place while you drop the screen assembly into the box. The box sides will hold the screen edges. After the screen assembly is in the box, you need to cut the fiberglass screen from the wicking and filler tube holes.
Cut an 18" piece of the 1 1/2" PVC pipe ( I used miter saw), then cut an angle on one end. Insert the end with the angle cut into the middle hole. This will be the filler tube.
Drill a 1/2" hole in the front of the box so that it is 1" below the inside screen. This is the overflow hole so the planter cannot be over filled and ensures there is a gap between the screen and the water for good aeration. You can put one of the tubes next to the box to get an idea of the hole height.
Use only a peat based potting mix in the box. Soil will not wick up the water. Mine are filled with Miracle Grow potting mix.
Fill the wicking tubes with potting mix and firmly pack it in the tubes, I really soaked the mix while filling the wicking tubes to make sure the were no air pockets. When the tubes are packed, start filling the box with potting mix. Wet the potting mix as you fill the box, making sure to pack the box so it fills with no air pockets. The goal here is to turn the potting mix into a big sponge that soaks up the water. It is important to fill the box enough to make a decent crown on top so rain water will run off. For a moisture cover, I used a trash bag with either a bungy or nylon cord to hold it down and put the plants directly above the wicking tubes (when planting tomatoes). I also used the plastic bin cover as a base to help protect the bottom, the greenhouse floor is crushed stone. You can follow the instructions on the Earthbox website for filling, fertilizer and plant placement.
They work great and are a good alternative to have a garden where an in-ground one might not be practical.