You may notice algae growing on the soil in greenhouses or polytunnels, or under any cloche tunnels. This is actually quite common at this time of year when the surface of the soil doesn’t really get a chance to dry out and with little air circulation and often some condensation inside a greenhouse, polytunnel or cloche tunnel.
At this point in the season, it shouldn’t be a huge problem if there is some algae on the surface of the soil, but you could run a hoe over the soil to scrape off the algae if you are concerned. Then, simply ensure that there is enough ventilation by opening a couple of windows or leaving a door open. Be careful not to overwater either – plants will not need anywhere near as much water now as they do in summer, and if you’re growing in beds under cover, there is probably a good amount of moisture in the soil. Try to water only when the top 2cm has dried out.
When it comes to spring planting, all you will need to do is scrape off the top level of algae and freshen it up with some new compost, either laid on top or dug in.