This is a surefire way to grow vegetables and flowers. It works year round in my zone 8 but for sure would serve well anywhere on a seasonal basis. It offers many benefits.
Plants have all the water they want. The water stays shallow which allows plenty of oxygen in the upper half of the pots. It works for 1 gallon on up. Long periods between rains might require some top watering. Usually bottom watering will suffice just as you would fill the bathtub. This helps keep down disease. Sufficient top watering is necessary to give transplants and germinating seeds a chance to grow deep roots. Once they reach the moisture zone, you can quit babysitting.
I use cheap potting soil and even straight composted cow manure from WM. I never throw it out, just add more goodies. I find worms in pots at the end of the season so it must be good enough. No problems with nematodes or any other soil disease. The steady availability of water eliminates most blossom end rot in tomatoes and peppers. I was surprised to learn that peppers love lots of water. It doesn't show in the photo but it's best to crowd the pots as much as possible to shade the surface to minimize evaporation. Healthy growing plants do use a lot through transpiration so you will have to learn through trial and error how often it is necessary to refill or top up the water. This method works with any kind of fertilizer or amendment.
So far I have not found anything that doesn't like it. The only problem I have had is with bulbs like lillies and amaryllis that die back in the winter. They will rot. Any bulbs that actively grow through the winter such as garlic and onions love it.
You can build beds anywhere at all. A level spot that you can easily reach with the hose is easiest. You decide on your dimensions and keep in mind you'll have to reach over and around to harvest. I started with a rectangular frame made of cheap 1 1/4" PVC pipe but wood or concrete blocks would also work. It's not necessary to be perfectly level but it helps to maintain consistency. You can put larger pots in the deeper areas. I got tired of buying pipe (26 beds and counting) so now I just use the same frame repeatedly to make a neat job and then remove it.
Job 1 is to have your area easy to dig. A tiller to break up the sod and then raking it out. Round Up. Newspaper and plastic. Whatever works for you. You can't have any rocks or tree roots to puncture your plastic liner and clumps of sod will rot leaving a low spot. If you can dig with nice straight lines, you may not even need a frame. It helps me eyeball for straight and level. I always have to dig out on one end and build up on the other. It doesn't much matter how deep or unlevel your sides are because we are concerned with the bottom and you can punch overflow holes at the desired depth. If you're going to use 5 gallon buckets, you probably need 3 or 4" depth. Keep your removed soil handy in case you need to make adjustments.
I buy rolls of 6 mil black plastic from Lowes. My beds are 10' long and 40" wide. As it comes off the roll, I cut a 12' length. Then I cut on the fold down the center. This gives me 2 pieces with good overlap on the edges so I can get a lot of beds out of a roll. A lawnmower can ride right over it to eliminate the dreaded weed whacking. Put down thick newspaper for added insurance against stones and roots, then the plastic. Straighten it out and weight down the corners while you add water. As it fills you can easily see how level it is and if it's off a little, no problem. Enjoy!
