11:21 - 10 January 2011
Some gardeners don’t enter their greenhouse in the cold depths of winter, while others relish the returning light and start their seed sowing in earnest. While it is very tempting to draw spring closer by accelerating your sowing programme, beware that you don’t end up with battalions of seedlings all needing warmth and mollycoddling for months on end, unless you have the time and equipment to nurture them properly. Look at the time scale carefully. Seeds sown now of tender varieties will require TLC into the month of May and possibly longer depending on the weather. That is a lot of TLC, lots of heating energy and still the risk that they may not make it. These days you can cheat a lot by buying seedlings that someone else (usually a dedicated mail order seed company) has mollycoddled in the coldest part of the year, thus saving yourself a fortune in greenhouse heating bills but ensuring there is not a gap in your production line. I’m not suggesting that you don’t put your greenhouse to good use early in the season, more that you build your seed sowing projects from small scale to large scale gradually as the season progresses. While mail order seedlings and plants can work out very expensive it’s a useful way to catch up too if you have missed a sowing or had a crop failure of some sort.
Consider sharing the burden with other gardeners. Why not sow a few extra and set up a seedling swap programme, where you grow something you love to grow and you swap the surplus healthy plants for something new?
With the prospect of spring just round the corner you can easily sow hardy seeds such as onions, peas, broad beans and sweet peas in January without heat and start to reap the benefits of these early sowings within weeks.
Don’t forget that there is a lot to be said for sowing seeds during April and May, so that when they are large enough to plant out the weather is conducive to do so. Most seeds can be sown within this time slot. It’s a good idea not to sow all the seeds in one packet at once, in fact sowing a few every fortnight will stager them so that they mature or fruit at different times.
But don’t forget that in all the excitement of harvesting earlier vegetables when the same produce is an extortionate price in the shops there is also great value in sowing later crops of the same to take over when the plants crops have finished cropping. For me picking beans and courgettes right up to the first frost is a great treat and keeps the surplus veg I’ve been freezing for use when there really is a gap in production.
The greenhouse really does extend the season at both ends, enabling the greenhouse gardener to sow earlier for earlier harvests and offering protection for the developing plants until they can be planted out or grown on in the greenhouse.
To get the best from your greenhouse it’s a good idea to invest in some dedicated seed sowing equipment. If you are starting out then a heated propagator is a brilliant purchase but you will need an electrical supply to power it. More experienced growers use soil warming cables sunk into greenhouse benches filled with sand, or a heated propagating mat. Again these require a power source and in a greenhouse it is vital that this is water proof and suitable for a greenhouse environment. Be sure to use a qualified electrician to set it up for you.
Ideally you need a thermostat though these will substantially add to the cost, but with a thermostat you can ensure that your seeds and seedlings are kept at the correct temperature.
When sowing into a heated environment bear in mind that the resulting seedlings will grow quickly and need somewhere frost free and warm to grow on. So don’t start sowing too early unless you have suitable conditions, i.e. a heated greenhouse area to grow them on.
