A Sustainable Life with James Strawbridge
PUBLISHED: 17:58 26 July 2011 | UPDATED: 19:45 20 February 2013
In his regular series, eco-celebrity James Strawbridge explains the benefits of growing produce under cover...
Top-quality local produce is what puts this area on the map, with many small producers and a huge amount of seasonal goodies being served up in restaurants around the county.
This month is the time to enjoy sun-ripened tomatoes straight from the vine, so I will explain some of the basics of growing under cover and enjoying your own Cornish tomato crop.
I have been growing tomatoes at New House Farm for a while and have found that the sometimes rainy weather can wreak havoc with outdoor tomato plants. From the same vegetable family as potatoes, tomatoes can suffer from blight. The solution is either to grow tomatoes upside down or under cover.
Nowadays, we are all used to being able to eat any type of produce at any time of the year, but it has to travel miles to reach us, so growing under glass or plastic enables us to produce exotic foods locally or at home. Growing under cover can be done in various ways, as described below.
A greenhouse has to be one of the nicest places in which to work, but choosing where to site a greenhouse is key. Ideally you want it facing south, positioned against a wall to absorb the heat, and with sunlight for as much of the day as possible.
Greenhouses can be expensive but they are available second-hand. Putting up a greenhouse can be tricky, but as long as you take care not to break the glass, then theyare relatively quick to assemble. They provide an excellent space to grow crops like tomatoes, aubergines, chillies, herbs, salads, and all sorts of seedlings. It should be about 4C at night during the winter and about 10C in the summer.
Giant plastic growing tunnels have proved to be highly successful commercially because of their relative cost-effectiveness and reliable growing conditions. However, polytunnels are not just for commercial farmers and market gardeners. I tried out our first polytunnel at the bottom of asmall garden in a rented house,and even though we lost a bit of space, we gained several seasonsof good quality fresh food. Always remember to dig down around the frame and lay some turf over the plastic to keep it stretched tight.
Geodesic domes, like the iconic ones at the Eden Project, provide passive solar energy and have a strong, aerodynamic shape. We needed a building to house extra tomato plants at the farm, so we assembled our own version.
Putting together a building that gains strength only when the last piece is put in place is a bit of a nightmare, but a lot of fun. The wooden frames are covered with plastic, stapled and siliconed together and finally worked into a jigsaw of pentagons and hexagons. This is officially called an omni-triangulated surface, but to me it looks like a spaceship. A geodesic dome provides lots of sunlight and a growing plot that maximises on vertical space, while its shape is perfectly suited to Cornwallsrolling hills.
Cold and hot frames
Cold frames can be made with an assortment of materials and are a traditional part of market gardening. Using rammed earth, concrete blocks, bricks or wood, a frame is made and then covered by a sloping piece of glass that faces towards the sun. The key design feature is that they can be opened and closed easily for weeding or harvesting, and they are ideal for growing seedlings, early and late salads and herbs.
Growing plants on your window sill may not sound like an aspirational approach to growing food under cover but it is one of the most successful. If you are a first-timer then it is a good place to begin. Young plants thrive in a warm, slug-free environment and because you see them more regularly they get more attention.
Tomatoes are another easy crop to grow on balconies, window sills, under cover and outside. At the farm we grow the majority of our tomatoes in small pots and trays, transplanting them to bigger pots as they mature. Keeping them in pots requires plenty of compost and watering but they do extremely well. I pinch out the suckers, which grow at an angle between lateral shoots and the main stem, to encourage bigger fruit.