As an avid gardener and buyer of mail order seeds, it’s likely that there will be various things that you do with your plants simply because… well, everyone does, and they’re supposed to work. One such popular tradition is putting ‘crocks’ – bits of broken pottery – at the bottom of your plant pots. It’s supposed to increase drainage, and yet it’s all nonsense, according to one new study.
Yes, we’ve all heard from those people who absolutely espouse putting ‘crocks’ at the bottom of a pot. They’re supposed to allow quicker water run-off than soil, in addition to stopping compost blocking the holes at the bottom of the pot. Don’t feel too silly if you’ve always thought that way, too – after all, Alan Titchmarsh, Monty Don and Gardeners’ Question Time are among previous endorsers.
The debunking comes from consumer magazine, Which?. Researchers each planted 40 pots with five “Million bells trailing yellow”, a yellow flowering plant that has been known to suffer root rot when combined with saturated soils. Sometimes a plastic pot was used, on other occasions a terracotta pot, while some pots had saucers, and others not. A note was made of the “vigour and flowering impact” of each of the plants. The outcome was that the crocks “made no difference to how well our plants did.”
Surely, though, it’s easier for water to flow through those bigger gaps where the crockery shards meet with the soil? That’ll doubtless be the view of many of our mail order seeds customers, but the RHS’s chief horticultural adviser Guy Barter disagrees, saying drainage is – if anything – likely to be worsened by broken bits of crockery, due to the block that is created. He instead advises having a layer of soil underneath the soil into which the water can drain, later being sucked up by the roots if needed.
Be reassured that crocks aren’t necessarily completely useless, as they might save you money on compost, in addition to blocking drainage when the weather warms up. Nonetheless, they generally just aren’t needed. Naturally, though, many of our mail order seeds customers are sure to keep up the ritual. There’s just something magical about crocks’ role in the heritage of gardening.