A coarse 'layer' at the container's bottom serves to reduce the volume of soil that will fit in the container and can make the container lighter, depending on what you use. but it doesn't aid drainage - only serves to raise the layer of saturated soil higher in the container.

If you're looking for a 'screening material' to keep the soil from migrating through the drain hole - why not try insect screening (like in your windows) or squares cut from plastic canvas (the stuff you buy in 9/12 sheets at a hobby shop for needlepoint).

Al

If you are having this problem I would look at what you are using for soil. With hundeds of pots and containers of all sizes I have never had this problem. I use the same mix as the commercial growers who also do not use anything to prevent soil mix from leaving by the drain holes. Al

I haven't had any problems with soil and drainage so far, because I am a novice in container gardening. I am just reading all the available books and articles on this theme, which provide me with the definite advice on draining. Do you think that drainage layer may not be used at all? May I do without drainage layer or shall I use something? What then-may it be foam plastic balls and some piece of old curtain fabric?

That "drainage layers" promote drainage is a myth that resists being laid to rest. You can read about the science HERE.

Al

So drainage layer may make plants roots suffocate from one hand, from the other hand-without drainage layer there is a danger of soil getting out of drainage holes. So what shall I do?

So drainage layer may make plants roots suffocate from one hand, from the other hand-without drainage layer there is a danger of soil getting out of drainage holes. So what shall I do?

Cover the drainage hole with insect screening. It lets water out, but keeps potting mix in. Get the plastic window screen and it will outlive you :)

But can you tell me whether you consider insect screening and a piece of old curtain fabric identical in their draining qualities? May they substitute each other?

loori, I use coffee filters and have not had a problem. The Melita ones are now perforated, but the old standard ones would work well also.

A couple of bucks buys a packet of plasticized mesh that is used to keep carpet from slipping around (ie: non-skid fabric not the under pad).
This stuff is washable, flexible & designed not to rot out under carpets; so I use it - easy to find, cut & lay in place.

If you are using a commercial planting mix with fertilizer incorporated then there is little need to fertilize. So should I then fertilize or not when growing peas in conatiner?