Polytunnel update: First frost brings summer to an end.

Last night the first proper frost struck. It wasn't expected, the nights have been mild and the forecast didn't indicate that temperatures were going to plummet like they did. However sudden frosts are not uncommon here and we have been awaiting their arrival.

In the polytunnel the early sun was bringing temperatures up again but the damage was obvious. Courgettes, tomatoes and the last cucumbers were unmistakably done for. It has been a good run and the cropping has been good on all but the cucumbers, I think they have found the heat too much for them this year.

So today's job was to clear out the tomatoes, only 4 small punnets of ripening fruit left, so that is good. They can go into the greenhouse to fully ripen. The strawberry plants under the tomatoes are also lifted and repotted ready for their new positions in the spring. I have weeded the bed  and added some well-rotted horse manure and replanted it with spring cabbage plants. The ground is very dry because I haven't been watering the tomatoes to encourage them to ripen the fruit, so it is very important to get the hose on the bed and make sure it gets a thorough watering.

The courgettes are in containers so they need only to have the top growth removed and then the containers are stacked and the compost will be reused for the early potatoes grown in pots in the polytunnel in the spring. Saves work and money. Just ensure any reused compost gets some fertiliser added to it and that it doesn't harbour any nasty pests or troublesome weeds.

Now the polytunnel is pretty much ready for the winter. The beds are full of winter lettuce, mizuna and rocket. Winter onions, raised in modules in late August, have been planted out, and the leeks are growing strongly. Kale, spring cabbage and the King of all winter vegetables - purple-sprouting broccoli are growing well. The broccoli plants are nearly as tall as me and promise a bumper crop in early spring. The asparagus is beginning to turn yellow and the fronds will be cut down and the crowns mulched but that is probably the last job I will have to do, apart from some watering.

It remains important to monitor the temperature and soil moisture levels as on sunny days temperatures can rise swiftly and the soil can dry out, even when plants are quite small. Remember that the soil will lose moisture directly to the air so if you can leave a surface mulch of dry soil over damp soil that will help minimise water loss. The best way to achieve this is by watering thoroughly and intermittently. Then water penetrates deeply and over the days when you don't water a surface layer of dry soil will form. Check how wet the soil is by scraping back this dry layer and checking what the soil underneath looks like. As winter progresses you should find that your need to water reduces significantly. Try to water on warm days and avoid opening the tunnel on frosty mornings until the temperature rises. If you have to go to work early, try asking a neighbour to help and reward them with some lovely fresh winter vegetables and salads!