Summertime: Slugging It Out

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slug note 1

We had one of the wettest sumer on record last year (2012), and it was our very first year of growing. Rain brought a number of problems – problems preparing the ground and planting crops; little crop growth; diseases and pests… especially slugs!

Slugs were everywhere. They could get into or under any crop protection, ate everything in their path, and seemed to increase in numbers exponentially. At times it was like we were farming slugs, not vegetables.

Certain crops seemed more vulnerable, or at least it made more of a difference to us. For instance, a cabbage with nibbled leaves is almost unsellable, whilst an aubergine with some bite marks is usually fine. We had to learn this, and then to assess each veg line on its sale-ability, and then whether it was worth us protecting and harvesting that crop.

slug note 2

The rain kept coming. We took to hunting slugs off the most valuable or delicate crops. Brassicas (cabbages, broccoli, cauliflower, etc) needed help in order to establish. Slugs were eating the outer leaves faster than the plants could grow new ones.. Polytunnel crops, same.

We hunted using gloves, a bucket with a thin layer of salt in it, and some rock-hard stomachs. Pick a slug off a leaf, drop it into your salty bucket, repeat, repeat, repeat. Hours later, rinse your bucket of salt doom out and try not to be too queasy. Hope it helps your plants survive another day, and try not to feel too guilty.

Did you know… There are over 30 varieties in Britain, but you’ll usually see, or see the results of, four of the common ones:

  • The Field Slug: small (up to 4 cm), usually grey/fawn in colour with darker flecks. Eats absolutely everything, and were tricky to see because they blend into mesh crop covers or look like small pebbles.
  • The Garden Slug: small slugs (up to 3 cm), black with a paler side stripe and a yellow or orange sole. Eats leaves and tubers, and blends right into the soil – hide and seek, anyone?
  • The Keel Slug: Larger slugs (up to 6 cm), usually dark grey/olive in colour, with a yellow or orange stripe along the back, with a pale sole. Spends most of its time underground, so is particularly destructive to root crops.
  • The Black Slug: can be very big (up to 20 cm). Colour is variable – white, red, orange or grey have all been noted, although black is most common, often with an orange fringe. The black slug may rock from side to side when disturbed. Causes much less damage than the other three – will eat new seedlings, but prefers rotting vegetation, fungi, etc, so will eat these when they can.

slug note 3

We are growing in as environmentally friendly a way as possible. That doesn’t mean that the slugs can stay – we’re farming for vegetables and have to be selective about what species can be on our land.

Under organic regulations we are allowed to use a few treatments, in moderation. We can use Ferrous Phosphate rather than Metaldehyde slug pellets, and Savona, which is a soapy water to get rid of aphids. These are things that won’t have any knock-on effects for other species, but instead harmlessly break down after first use.

In addition to the limits on use imposed by organic regulations, we are limited in use by price. It is so expensive to use most of these products that unless the problem is alleviated in one or two uses, the cost can quickly outweigh the value of your crop. This was our introduction to organic growing risk and loss. There were things we had to give up on entirely, like spuds (which got hit with not only slugs, but blight and wireworm!) and celeriac. And there were things where we had to stop looking and just hope for the best, like cabbages and beetroot.

slug note 4

Our soil is very heavy clay. It’s nutrient rich, which is great, and it stays pretty damp even on dry days, which can also be great, because we don’t have to water much. But it also means that slugs, which burrow in, and travel through, soil can get around easily.

The dry and heat we needed finally came for a week at the end of July, in bits through August, and finally some more in September. But by then it was too late for many crops – we’d lost all the courgettes by then and had low hopes for the squash, sweetcorn and a few other things. But the dry finally drove the slugs down, which was a relief. We’d also learned some important things:

  • Leave a wide border between grass paths and crop beds. Hopefully this will act as a physical barrier to slugs getting into crop beds.
  • Raise seedling trays off the ground, or you’ll find cheeky nibbles taken.
  • The slugs under the salad heads tend not to eat your salad heads – they just like the shade!
  • Slugs in the compost heap are your friends… so if you don’t want to kill them off, drop them in the compost instead.
  • Sometimes you just have to give up!

Hopefully we won’t have such a drastic summer next year. But thanks to this past year, and the explosion in slug population, hopefully it will mean an increase in the things that eat them, which is what we need to focus on encouraging over the next months (and years). We need carabid beetles, hedgehogs and birds in big numbers, happily munching away at those pestilential pests.

Meanwhile, at least we know the slugs approve of what we’re doing…

slug stamp of approval