There is no definite beginning nor end to the gardening year – the seasons cycle round indefinitely bringing constant change but never anything as defined as a start or a finish. For me though, the annual spreading of compost on the beds feels very much like a fresh start in the allotment, with the plot looking like it is revitalised ready for spring (even if spring proper is still many weeks away). This ritual could happen any time from autumn, but mid-February is invariably the time when I get round to it.
Mulching the beds is part of our ‘no-dig’ approach – each year we top up the beds with 1-2 inches of compost which gradually gets drawn into the soil through the year by the worms. This layer of mulch does a number of things – firstly, it suppresses weeds because any annual weed seeds find themselves too deep to germinate, while perennial weeds may break through in a weakened state and are easy to pull out with a trowel; secondly, it helps retain moisture in the soil which means we don’t need to water our plants as often, whilst also improving drainage to prevent water logging; thirdly it feeds our crops through the year, or more accurately it feeds the soil and its fauna (fungi, microbes, worms) which in turn make the nutrients available to plant roots. The nutrients in compost are generally insoluble meaning they don’t wash away in the rain (unlike with nitrogen fertilisers) and will slowly release their goodness through the year. This means we generally don’t bother with any supplementary fertilisers except for plants in pots. Fourth, and in a way directly related to the other points, is that not digging the soil means that the soil develops a natural and healthy structure, aerated by the action of worms. This mimics the way a soil ecosystem works in nature – organic matter (ie dead leaves and plants) fall on the surface and is broken down by microbial and fungal action and drawn down into the top soil by the worms. No digging required!
That’s the theory. The reality can be that while it certainly saves effort by not digging, you do need to source considerable amounts of compost each year! ‘Compost’ can be any decomposed organic matter – garden compost, rotted manure, leaf mould, mushroom compost. While it would be lovely to use homemade compost most of us don’t produce enough of it for our needs. In our first year of growing we were buying bagged ‘organic soil improver’ which is largely composted green waste. This is good stuff, relatively low in nutrients (but just enough to steadily feed your plants) and ideal for planting straight into, but very expensive to buy in bulk at 3 bags for £10 (not to mention the long term damage to my suspension after multiple trips back from the garden centre with the car stuffed full of bagged compost). Since then we’ve discovered our local council will deliver 1 tonne of their green waste compost (made from the trimmings and prunings from local parks and gardens) for £21. Great! 1 tonne is just enough to cover most of our plot, and the compost is produced at such a high temperature (it arrives literally steaming on the back of the truck) that it is reliably weed free. However, this does make for a back breaking day each February as we wheelbarrow 1 tonne of compost from the front gate of our site up the hill to our plot at the back.
One thing I am becoming aware of is that compost and manure tend to be slightly acidic, and so adding large amounts each year will gradually lower the pH of your soil. This can be a problem for a lot of vegetables, which tend to prefer a neutral pH (7), and in particular brassicas which can be more susceptible to diseases like clubroot when growing in acidic soil. So this year I’ll be raking in some cal-sea-feed to raise the pH, which should hopefully help us avoid any problems.
For more info on ‘no-dig’ do check out Charles Dowding‘s website and books.