The gradual seasonal change from winter to spring can be a frustrating time for gardeners. A rogue sunny day may well lift our spirits with the promise of longer, warmer days to follow, but more often than not a sudden frost sends those hopes back into the cold. Fingers twitch, garden tools at the ready, as you gamble on when the time is right to cast seeds into the soil – do you go early for the longest possible growing season with the risk that a prolonged cold spell could scupper their chances of success?
For those gardeners who, like us, are eager to get going with the fun jobs of sowing and growing, it’s possible to cheat the weather a touch by warming up the soil in advance, giving seeds something of a head start. Here are some tips on how to achieve this…
Improving the quality of your soil will help to warm it up. Soil that is lacking moisture loses heat quickly, while saturated soil will take longer to thaw following a cold snap. So by digging some good manure or compost into your soil a few weeks before sowing seeds, and covering it with an extra layer of manure on top, you will not only enrich it with beneficial nutrients but you’ll also improve its condition and make it more suited to the seasonal weather. Compost also carries on decomposing over time, releasing those nutrients and giving off heat in the process (notice how hot a pile of compost gets in summer as a result of it rapidly decomposing). Good compost really is your soil’s best friend.
Fleece or Plastic Sheets
It’s well worth taking advantage of any winter sun that shines by covering your soil with something that will maximise its heat and lock it into the ground. Horticultural fleece is an ideal medium for this task – it can easily be spread over the area you want to warm up and pinned into place with pegs or bricks. And you can keep it covered over your seedlings as they emerge to allow them to grow as if out in the open – fleece not only lets in sufficient light but it also allows water to get through.
Alternatively, you can use sheets of plastic, which are particularly beneficial if you want to dry out soggy soil as well as warm it up. Black plastic will do the job but you’ll have to remove it when it comes to sowing as your young seedlings will need light in order to grow. We find clear plastic preferable, although you’ll obviously need to lift it every time your seedlings need watering.
Garden centres provide any number of sheeting options for this purpose, but we prefer to recycle and save bubble wrap throughout the year for this task. It not only provides the necessary insulation but is easy to peg out too.
Cloches and Polytunnels
The absolute best way to get ahead of the weather is to invest in a greenhouse, but if space or budget is prohibitive then you might like to consider a cloche instead. These are protected coverings that were originally designed to look like mini bell-shaped greenhouses (‘cloche’ is the French word for ‘bell’) but now come in all sorts of shapes and sizes, along with their elongated neighbour, the polytunnel.
Prices for cloche structures can be quite steep, especially if you want to invest in something that will last, but there are plenty of ways to make your own. Any clear plastic tub will do the job – from small food trays for seedlings, to large buckets, or plastic bottles with the bottom cut off (the hole in the top also helps for ventilation and watering). If you want to be a little more adventurous then you can stretch clear plastic or bubble wrap over a suitable frame, or even go large and build your own polytunnel. For this, it’s simply a case of creating supporting arches (wire is your best bet), or upturned ‘V’ shapes from wood, and wrapping the plastic over the top before pegging it to the ground on either side. Make sure your covering is longer than the polytunnel so you can pull it down at both ends for all-round shelter. For extra strength, it’s worth fixing a supporting pole (such as a bamboo cane) to run along the top of the frame before the plastic covering goes on.
Whatever route you choose, even a degree of extra warmth could be the advantage that your seeds need for an early start this spring.
What seeds are you thinking of sowing early this year? Let us know in the comments.