Extending the growing season

Extending the growing season here in the north, where the growing season is short, is precious for us. The contrivances we take are many – with everything from starting seeds indoors so that the plant gets a sufficiently long growing period to carry a harvest to building greenhouses where we can grow things no matter the season.

Starting plants indoors

Starting plants in your house gives hope for a new spring and summer. In order to grow and harvest some plants here in the north, it is necessary to start them indoors first. Some other plants enjoy it as well since it gives them a better chance to survive once they get put outside. However, it is quite space-consuming to do this on a larger scale, and you need to have a genuinely bright place for them. If you do not have enough light, it is possible to solve this with different lighting setups. If you are entirely unable to start them at your place, you may be able to house your plants with someone with better conditions.

Using cold frames and hotbeds when extending the growing season

A cold frame is a small, low greenhouse. With a simple cold frame consisting of a solid frame and a transparent lid, you can extend the growing season by about a month during both spring and autumn.

The longer side of the cold frame should be turned slightly to the southwest, and the rear wall should be higher than the front to get the most out of the sun. The tilted lid also makes snow and rain slide off easier. Materials for the frame can be concrete or wood, and the lid any material that lets the sunlight through accurately. It is common to use old windows. To make the climate in the cold frame even better, you can insulate it with soil, leaves, or straw around the outer walls.

If you want to extend the season further, you can instead make a hotbed. To increase the heat in the bed, one begins by laying out a thick layer of fresh horse manure mixed with lots of straw. The thicker you make it, the warmer it will be. The next step is to pack in the manure firmly – easily done by walking on it – and water it with hot water, preferably with added urine, to speed up the heating process. You can then set the frame in place and put the lid on. You then barricade the frame with straw all around it. Soon the heat will start to rise and then begin to fall again. When the temperature has come down to about 30 degrees Celsius, it is time to add the topsoil and start growing things!

Keep in mind that it may get sweltering underneath the glass when the sun’s rays start to warm. Therefore, you need to keep a close eye on the temperature.
Photosynthesis gradually decreases when it gets to be above 25 degrees Celsius, which also reduces growth and production. The further along in spring you come, the more often the cover needs to be lifted during the warmest hours. Another way is to cast shade on the beds with, for example, reed mats or old rugs.

With the help of both cold frames and hotbeds, you can get fresh leafy vegetables much earlier in the year. A hotbed can provide its’ first harvest as soon as in
February.

Extending the growing season with greenhouses

For many, the dream is to have a greenhouse. It can be anything from a small greenhouse built from old windows next to a southern wall to a large garden greenhouse. The range of greenhouse kits is vast, but they cost quite a bit. But if you are good with tools, you can build one yourself by putting up a wood frame that you then cover with construction plastic. Another option that is cheaper than regular greenhouses is the so-called arch greenhouses, which have steel frames covered with plastic tents.

All greenhouse frames must be anchored well into the ground so as not to fly away as soon as the wind picks up. Greenhouses made from glass are in themselves quite heavy. For these, you only need to screw the body properly into the underlying base. When it comes to plastic greenhouses, you can bury the edges in the ground. Still, a better way is to build a rail inside the greenhouse against which you then attach the plastic. If the place is windy, you may need to create a natural windbreak out of plants to protect it.

I will not go through the ups and downs of growing in greenhouses since there is already a lot of literature on the subject. However, there are several good ways to combine a greenhouse with another house, which less often brought up. Thus, here it is.

Greenhouses combined with outbuildings 

Connecting a greenhouse with another building has many advantages, provided that you put the greenhouse on the side of the house where you get the most sun. The most significant advantage is that you save a lot of energy – both in the greenhouse and in the adjacent building. Having a glass wall to the north gives no merit as far as the sunlight goes; rather, this only leads to energy losses.

Depending on what you have in the other half of the building, you can even create an additional energy supplement for the greenhouse. The previous page shows a way to combine a hen house and greenhouse.