Slugs in the polytunnel

The weather may be getting colder but the slugs are still active, particularly in the polytunnel.

I am fortunate to live on a beautiful croft, with a wide variety of wildlife. Many of these help to keep the slug population down but unfortunately they do not always have access to the polytunnel. During the summer the tunnels often have a resident toad or two, but at this time of the year they tend to find a hibernation spot. This leaves any plants more vulnerable to slug predation, and with growth slowing down slugs can make a big impact.

Because of the natural slug and snail predators I am generally loath to use pellets. However during late autumn and early spring, when the tunnels are generally closed most of the time and the predators are hibernating, I do admit to scattering a few organic pellets around vulnerable plants.

Today I was planting out some winter lettuce, having just cleared out the tomatoes. The lettuces have been waiting patiently in the greenhouse and are a fair size now, but as I was forking over the soil I couldn't help but notice the quantity of baby slugs and snails there were. They would be delighted by my new offerings and after all my careful nurturing of the lettuces I could not afford to lose them overnight.

Last week I picked over the purple sprouting plants and took a good handful of slugs to the hens. Pellets here are no good, the slugs are not interested in leaving the canopy of the broccoli. The only way of reducing their impact is careful hand picking and waiting for the colder weather to set in, when they will seek the warmth of the soil. Then as things begin to warm up again, a few pellets or some beer traps will catch quite a few returning to the feast.

In the spring pellets are judicially employed to protect seedlings. I never use them outside, but the polytunnel provides too good an environment for slug and snail breeding. They can often have three generations in a year in the tunnels, and the baby ones, hard to spot but ravenous, are the worst. Beer traps don't seem to interest them, so using pellets to mop up a few just hatching from the soil seems to be the best method.

In the summer, if you feel things are getting out of hand, try nematodes. These natural predators of soil living slugs will make a significant impact when the soil is warm. You get the nematodes from a good gardening product supplier and add them to some water in a watering can and water them over the soil. They will increase the natural population of these nematodes and will continue to be active during warm weather for a number of years.