Damping off disease

Posted: Wednesday 1 May 2013
by Pippa Greenwood

Damping off disease is a nightmare during spring. As the exciting cycle of seed-sowing continues apace, this insidious disease is waiting in the wings.

In those wonderful James Herriot stories, there is a woman called Mrs Pumphrey, whose spoilt dog is known as  ‘flop-bot’. With a name like that, there is no need for a description. When a tray of seedlings suffers with the horticultural equivalent, and the whole lot keels over in a miserable heap, we use the less helpful name of ‘damping off disease’.

Damping off disease is a nightmare during spring. As the exciting cycle of seed sowing continues apace, this insidious disease is very much waiting in the wings, ready to cause devastation among seedlings.

The various fungi responsible are generally soil borne, and thrive in damp compost. They find the very fragile young roots and stems of seedlings an easy conquest.

But how does the fungi get into the compost? The answer is partly to do with unclean water, such as that from a water butt. By the time rain has washed over the roof, along the guttering and down the drainpipe, and then sat gently festering in the butt, it has often accumulated and ‘brewed up’ one or more of the organisms that can cause damping off.

I’m not saying don’t use water butts, but it’s well worth taking care with what plants you use the water on. I use water butt water on more mature plants, and on those in open ground. I prefer to use mains water for seedlings and very young, or tricky, plants.

If the seedlings are at all etiolated or leggy and drawn (usually because they are too close to each other and are lacking sufficient natural light), damping off is also more likely to strike. I always try to sow my seeds fairly thinly and keep the seedlings in a very well lit spot. If you grow your seedlings in the house on a windowsill, they are likely to get a bit drawn. You can provide them with extra light by putting a sheet of tinfoil clad cardboard behind the trays and pots, to reflect useful light from the window back to the plants.

But, if you are unlucky and your seedlings do succumb to damping off disease, bin the offending seedlings and infected compost and start again. Remember to keep your growing conditions as super-clean as you can.

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