The tomatoes that started in the greenhouse need planting out now – a little late but life and half term had their own ideas, so a couple of weeks ago I potted them up into big pots to keep them ticking over, and now is the moment to get these big brutes into the polytunnel. The polytunnel is managed strictly on a ‘no dig’ regime, and it seems to work brilliantly for the tomatoes. ‘No dig’, in case you haven’t come across it, is a way of managing the soil. There is a little more to it than simply not digging, but not digging is at its heart, and the logic goes that the soil and its microorganisms are a happy community that are in better shape left undisturbed than continually churned up.
The trick is to lay thick layers of mulch on to the top of the soil and then allow the worms to work them in in their own sweet time. This worked particularly well on my polytunnel soil partly because no dig is also a great way of reclaiming unworked soil, and ours was in quite a state when we started. Having little space we sited it onto a rough area of ground and thought we would clear it later, but the soil being clay it quickly baked hard once the polytunnel was up, and became impossible to work. Oh no! But no dig is the perfect solution for such awkward spots. After chopping back the weeds we put a layer of rotted manure over the soil, then a layer of cardboard and thick wodges of newspaper, all followed by a final thick layer of compost.
The idea is that the bottom layer starts immediately being taken down into the soil, softening and improving it, the cardboard and paper blocks out light to smother weed growth and slowly rots down, and the top layer of compost can be planted into immediately. We had a bumper crop that year and have every year since. Of course weeds grew through and around the cardboard, but once the ground had been softened these proved easy to pull out, and repetition has reduced even nasty couch grass to manageable. If you are not trying to clear new ground you don’t need to bother with the cardboard and paper, and can just pile on lots of bulky organic matter and plant straight into it. And then to maintain the bed? You’ve guessed it: an annual application of lots of compost or manure. We have created ‘no dig’ beds all over the allotment, and it is great everywhere, but seems to work particularly well in the polytunnel, where there really isn’t enough room to be digging properly anyway.
It might work so well for tomatoes because of their particular growing needs. Tomatoes have two different types of roots: the deeper roots take up moisture, while a network of surface roots absorbs nutrients. In a system where a new load of organic matter is being added to the soil each year the depths will be moisture retentive from previous manurings, and the surface will be full of nutrients, the perfect tomato combination. It is definitely worth a try, particularly if you are at this stage of the season and already running out of ground on which to grow your crops, or if you have a particularly tricky area of soil to conquer. I know that it’s a brilliant solution for the polytunnel, and that my late planted tomatoes will be at their happiest and their most productive – and be most likely to catch up – with their feet in ‘no dig’ soil.