I live in SC just across the state line from Charlotte NC. For the past 3 years I've done basically what you're wanting to do with several modification ... thus, turning all my plastic pots into self watering systems. (1) I drill the side holes in four locations around the pot. (2)I put growing media in the pot up to the drilled holes. (3)I place several layers of DuPont 15 year landscape fabric in the pot, making sure to cover the bottom completely ... this stops roots from getting into to the bottom of the pot. An alternative is to skip the landscape fabric and use Smart Bags ... or any fabric bag. Works great! I've used it for pots from 12" to 24" dia and have planted tomatoes, roses, and all types of large plants (Russian Sage).

Some pots are sold as self watering containers ... they hold water in the bottom and have recessed areas in the reservoir platform to allow soil contact with the water (just like Earthboxes, Earthtainers, Garden Patch, etc.) With these pots, I simply drill the holes in the side of the pot, at the level of the reservoir. To make the reservoir larger, I have placed growing medium on top of the reservoir platform and then added the fabric cloth and growing medium or fabric bag. Drill your holes in the pot at the fabric cloth level.

In some pots, I put a rock or rocks on top of the landscape cloth or in the bottom of the fabric bag .... the rocks are for weight only ... keeps the plants from blowing over!

Plus, I have a drip system hooked up.

Best of luck. It works for me

Tony

Tony, wow.. Not bad instead oc buying expensive self watering pots.

As for I? I use insect screen or plastic grids with hiles used for, I wish I knew the name of that hobbie found at any crafts store and place them over the hole if I wants drainage but no mix to fall out.

Mike

No need for rocks, use screen material from Lowes for windows.

Insect screen, cross-stitch frame, plastic dry-wall mesh, bonsai screen.....
anything durable with small grid-work.

Josh

So rocks are totally bad and totally out of the question?
Won't metal screen rust out? I once had some screens for plant bottoms, sold for that purpose, but they did not last very long either.

Rocks reduce the root-space available for growing.
With a more water retentive mix, rocks would also raise the level of the perched water table;
but you don't have to worry about that since you're using a well-draining mix.

The metal screen that I have is aluminum, I believe.
However, the recommendations are for fiberglass insect window/door screen.

Josh

I just drill about 8-10, 1/2" holes in the bottom.
Never really notice any potting mix washing out, not enough to worry about anyway.
No screen, no rocks, just nothing but potting mix.

I use fiberglass insect screen. Over time it can deform and such, but I've had some in pots for over a year and no sign of problems (it doesn't need to be very strong).

It will also support a slight perched water table (I have this problem when draining food in a strainer), but that isn't significant for a well-draining and well-breathing mix (and a more water-retentive mix will have a PWT anyway).

I bought some bonsai mesh on eBay at a good price, so that is what I will use. Thanks

Usually I usually do is use a gravel chunk or a bit of bark to partially close off each hole. Once the mix around the holes is wetted and weighed down by what's above it it stays in place, but you have to keep it in the pot before you can get that far.

I've also used newspaper.

I use shards from broken terra cotta planters. They're slightly curved, so they let some water out, but not so curved that it lets out a bunch of soil too. (The soil gets out, but not quickly.)

I tried pebbles and styofoam peanuts, but don't recommend either (particularly the peanuts. Oy vey!) Sooner or later, you have to remove old soil and put in new. Soil didn't seem to have a problem slipping through the pebbles and styrafoam peanuts, so it was hard to separate the two. (I put the old soil in our neighborhood park, near their landscape plants. It's not terrible soil, just not good enough to grow good veggies in anymore., and I can't really thorw out big bags of soil.)

I wish I knew about the fabric idea a couple of months ago. I just repotted soil in some big pots. (Unfortunately, one had packing peanuts in it, so it took hours sifting through that crap. Dumb idea learned about several years ago on this site. lol)

I guess it is impossible to kill these gardening myths that keep being supported, no matter how many times they have been debunked. Al

Fiberglass drywall tape. Available at any hardware store in rolls. Cheap, easy to cut to size, self-adhesive (for when you're first filling the pot) and durable. A single roll will cost you maybe $8 and screen the holes on hundreds of pots.

It's all I use now.

I use coffee filters,a lot of cluck for my buck!! Also use broken pieces of terra cotta,and packing peanuts.

For things like orchid pots,i use my wood burning tool to burn the holes in the side of the pots,a lot easier than using a drill,don't have to worry about the pots cracking.We're talking plastic pots here!!
kathi

I've got a good sized Hoya in a pot with rocks on the bottom, but that's just because it's indoors where the water can't be allowed to run out onto the carpet and it's too large to easily move to a sink when watering. The pot sits on a saucer to catch the water that runs through and the rocks (in theory) keep the soil above the standing water.

Is there a potential problem of toxicity in using aluminium window screening for drainage at the bottom of pots (for tomatoes)?

I use window screen from a sliding screen door my Chocolate Lab ran through. I also use some neat plastic screeny-things I found knitting/crocheting/whatevering department at Michaels craft store. I got 8 for $1.49 and they're round and fit the bottom of a pot perfectly, with no trimming necessary.

I used to put pieces of busted pots in the bottom, but I read that doesn't help, so I stopped doing that.

matthew_p,

no.

So many products are sold in plastic mesh bags, such as onions or potatoes, I never have to buy anything for this purpose. Calistoga Al