Putting Bits of broken terracotta pots at the bottom of plant pots to improve drainage : RHS
Affiliation between RHS and Gardeners Association

The Royal Horticultural Society, to which the NLWGA is affiliated, is seeking closer links with associations like ours, were they are able to provide solutions to gardening problems that many of us amateur gardeners cannot. Furthermore, the RHS will advise on new problems facing gardeners (such as the spread of the New Zealand flatworm that devastates earthworm populations) and possible solutions. They are also seeking our help in gathering country-wide information.

Our committee member Malcolm Greenhalgh has recently taken on the role of linking between us and the RHS and below are some of the recent problems they have advised about. We will try and update the site regularly with further details. If you have comments or experience with any of these please feel free to add your comments by using the comment links. Hopefully we can all benefit from our affiliation with the RHS by learning that little bit more about the plants that we grow. We will collate and feed back to the RHS.

If you have experienced other gardening issues you would like Malcolm to take up with the RHS please email details of these to us using the email links below, and we will endeavor to seek their advice and post  response for all to read and learn from

RHS Membership can be yours at a discount price, and our Association will make a fiver if you do! Advantages: 12 issues of The Garden every year (the best gardening magazine); free entry into RHS gardens (as at Harlow Carr and Wisley); members’ day at RHS shows (e.g. Tatton); a free advice service. If you are interested, please contact Malcolm Greenhalgh.

Putting Bits of broken terracotta pots at the bottom of plant pots to improve drainage

by Malcolm Greenhalgh on 03/28/13

My grandfarther, who started me off gardening over fifity years ago, taught me always to put bits of broken pot at the bottom of plant pots so that excess water will drain away quickly. Recent research, however has shown that this is not only unnecassery, but that there are far better ways of going about it. Apparentely those bits of pot do not aid darinage; instead they create what soil-water scientists call a "perched water table". In other words, the crooks do not enhance drainage, but they hinder it.


What they suggest as a far better approach is to mix plently of grit into the potting compost (since I read about this I have been putting one unit of grit to nine units of Sinclair, Clover or other non- soil compost .. it seems about right). I compared this with a large pot containing crock at the bottom and with pure Sinclair compost on top, and found that drainage greatly improved and that the compost was not so heavy and stodgy (i.e there was more air in the compost, and plant roots need lots of oxygen). Of course, with no crocks the plant also has more compost for its roots to penetrate. the grit we sell at the Hut is ideal.

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