The tomatoes started so well this year. We grew them from seed (Gardeners’ Delight) on a windowsill. They germinated quickly, grew strongly, and it wasn’t long before they needed potting on. When the weather had warmed up, we moved them into the greenhouse. Flowers came, followed by nascent fruits. We potted them up into their final, large pots. They continued to grow. But we began to notice some curling in the leaves. The new leaves, as they came, didn’t look quite right – too thin and spidery. There was clearly something not quite right, but it wasn’t until recently that we noticed just how bad things had become…

Not a pretty sight, is it? But what could be the problem? A virus, maybe? The lower, earlier leaves had curled a little, and had brown and yellow markings, but it wasn’t blight, because the plants weren’t so much dying as becoming hideously deformed. It looked like an example of weed killer damage, but how could that be, when we don’t use any weed killers in the garden, and when we generally buy organic, peat-free compost? I did wonder whether it was drift from the weed killer used on the adjacent farmland, but I don’t think the timing was right, and it’s unlikely enough would have drifted into the green house to cause the problem.

I sent pictures to the RHS for their advice (you have to be a member to use this service) and the answer came back that yes, it almost certainly is weed killer damage (to which tomatoes are very susceptible) – almost certainly from the compost. The RHS expert didn’t seem especially surprised. It seems that there isn’t too much control over the material that goes into compost.

Weedkillers are used extensively, including by councils, on roadside verges etc. ‘Weed & Feed’ type products are used in large quantities by householders on their lawns, which then grow like Billy-Oh. The clippings are sent to be recycled by the local council, who sell on the resulting compost (which, of course, will be heavily contaminated with chemicals). Perhaps this is one of the problems of avoiding peat (which, I would guess, is free of chemicals in its raw state) – you have to make compost from other materials, which may not be so pure.

We need to continue to move away from using peat, because of the degradation its extraction causes to the environment. But makers of compost really should be ensuring the material they use isn’t contaminated. Particularly if they’re labelling it as organic.

Annoyingly, we can’t remember which compost we used for the tomatoes. We potted them into their final pots early on during the lockdown, when it was very difficult to get compost. We had to bite the proverbial bullet and buy a few bags of non-organic compost from the Co-op. It may well have been that batch that was contaminated. But I’m not going to make any allegations at this stage.

We took offsets from the plants before they started to distort. It’s easy to do – you just pick out a reasonable sized side shoot, pop it into compost, and it roots in no time. These plants are now a good size, and are setting fruit. We’re taking no chances with them – we’ve planted them outside, in the soil (there isn’t much room left in the greenhouse anyway). It will be interesting to see how they progress, but so far, they’re fine.

I’ve got a plan for next year. I’m going to record what compost we use, and I’m going to grow one of the plants in soil from our garden, as a control. If that plant is OK, but the others have the same problem as this year, I’ll have evidence it’s the compost – and I’ll be straight on to the manufacturer. I’ll let you know what happens, and I’ll name the culprits if there is a problem.

For this year, there are some fruits that don’t seem to be affected lower down on the plants, and they’re beginning to ripen. I just hope they won’t poison us!

As a great robot used to say, ‘What a bummer Buck’…

text & images © Graham Wright 2020