Recurrent frosts are an eternal headache of summer residents. How many plants they have destroyed, how many tears have been shed because of them – it is impossible to count. Often the temperature drops so low that even greenhouse crops are under threat. Unfortunately (or fortunately) we have not yet learned how to command the weather, so we have to adapt to its “surprises” — to protect plants in greenhouses from frost.
Wouldn’t it be easier to wait for stable heat?
There is no definite answer: it all depends on what goals are your priority. To get a decent harvest, you will have to think over a protection strategy, choose an acceptable option and plant seedlings in due time.
If you want to wait for stable heat, it’s your will, but consider two nuances. Firstly, frosts can come even in June, and what to do with overgrowing seedlings until then is a question. Secondly, the optimal age of planting for each crop is not an empty phrase. Overgrown plants take longer to get sick, take root worse, later give the harvest. For example, about an important feature of the development of cucumbers: in phase 6 of the leaves, they begin active growth of the root system, and by this time they should already be sitting on the bed. Otherwise, at best, the development of plants will stop, at worst – they will die.
Methods of protection
Well, now let’s go directly to the methods. I tried to collect as many different ones as possible, but if I missed some affordable labor-intensive method or you have an interesting solution, by all means tell us about them in the comments, okay?
Greenhouse
I like this method: it is not difficult to put and remove the greenhouse, it does not take up a lot of space in the shed in disassembled form, and most importantly, it protects the seedlings reliably. Under the shelter of spunbond (60 g/m2) in a polycarbonate greenhouse, tomatoes and peppers survived frosts up to -5°C without loss.
Individual “fur coats”
There are many varieties, but the essence is the same — a personal shelter for each plant. Since we grow seedlings not by the piece, but by tens and hundreds of roots, budget improvised materials are usually used.
Plastic bottles: with all the dislike for this material, I must admit that lightweight, durable containers do an excellent job with the task. Under such a shelter, even in the open ground, cucumber seedlings withstood night frosts up to -3 ° C, which lasted a week!
Yes, I don’t like beds lined with plastic bottles, but if I have to choose between an aesthetic type of shelter and the preservation of seedlings, I will not hesitate to choose the latter. In my opinion, this method has only one drawback: it will take a lot of storage space.
Glass jars: suitable for hiding seedlings, since plants with real leaves are problematic to squeeze into a narrow neck. However, when there is nothing else at hand, and a decrease in temperature is expected at night, the seedlings will have to be patient. It’s better to break a few leaves or even plants than to lose the whole lot.
Tents made of newspapers and cardboard: paper is a good heat insulator, so it will definitely be useful for protecting heat—loving crops. With regard to saving time, cardboard boxes are very convenient: you do not need to make anything, just put it on the bed, and that’s it. Just in case, bury a little or sprinkle the bottom edge with earth, leaving no chance for the cold air to get under cover.
With newspaper tents will have to tinker a little, but nothing complicated. The author of the method recommends making them multi-layered, and to further enhance the insulating effect, how to crumple newspapers. The essence of the impolite treatment of periodicals is clear: to increase the air gap between the sheets of paper. The tent itself is easy to make: roll up the cone of the desired height and volume, fasten the edges with a stapler or tape (you can do both), put it over the plant and sprinkle the edges. In theory, I like the method and it seems promising, but how it will work in practice is unknown.
Hay and straw
I doubt the effectiveness of this method, but the author assures me of its absolute effectiveness. The idea is this: plants need to be covered “with a head” with hay or straw, and not with a dense layer, but loosely. For specimens growing near walls and doors, the shelter layer may be slightly thicker. That’s all, actually. If anyone has tried to protect seedlings in this way, tell us what happened in the end — it’s very interesting.
Hot water
There are several use cases, depending on the degree of temperature decrease. With a slight cooling, it is enough to put several buckets of boiling water in the greenhouse in the evening. If the forecast promises a serious minus, you can additionally pour hot water on the path between the beds. Some advise in addition to sprinkle wet soil with dry, so that the earth cools down more slowly. For all its simplicity, the method is reliable, proven in practice, so use it safely!
Water in containers
Perhaps this method claims to be the first line in my personal rating. Several tanks (cans, bottles) with water are placed in the greenhouse. During the day, the sun heats the water, and at night the tanks work as heating batteries. According to the reader, who has been protecting her plants in this way for several years, water bottles have been standing in her greenhouse for years, so you don’t have to worry about sudden return frosts — they won’t be caught by surprise.
Fire to help us
The most familiar way to protect yourself from the cold is fire. I would like to use it to my advantage, but how? It is dangerous to make a fire: plants can suffer from a strong fire, and if the greenhouse is film or polycarbonate, then it will not be lost for long. But are summer residents used to overcoming difficulties? A solution has been found, and not one!
Candles
Even such a small fire source is able to withstand freezing. For safety reasons, the candle must be placed in a container made of non-flammable material (a pot, a metal bucket, a ceramic pot).
Additionally, a heat storage device can be placed on the container — brick, cobblestone, etc. In the evening, light a candle and go to sleep quietly; by morning it will go out, but the heat storage will not have time to cool down yet. A small nuance: try to install the candle strictly vertically, then it will burn as long as possible.
By the way, take note: a decent alternative to quickly burning candles is homemade oil lamps or good old kerosene lamps.
Barbecue
The method seemed laborious to me, but I must pay tribute to the author of the idea — he tried to provide all the important nuances.
The essence of the method: in the open air, a large fire is built in the grill so that there are a lot of coals. As soon as the flame has fallen, they are sprinkled with sand or ash — so they will smolder longer. The hot brazier is carefully transferred to the greenhouse and placed approximately in the middle; on the sides (from the side of the beds) and on top are covered with sheets of slate or asbestos. Then a high greenhouse made of film is placed over the beds and barbecue. According to the author, these measures are more than enough to protect seedlings in a polycarbonate greenhouse even at -15 °C overboard.
Heaters
I will mention them briefly, since this method of temporary heating of greenhouses is probably known to everyone.
A friend saved seedlings in a small film greenhouse with a small household fan heater; many summer residents speak with approval about infrared heaters. Since we are not talking about a permanent form of heating, both an electric fireplace and a wall convector can be temporarily relocated to the greenhouse, if only the precious seedlings survive!
What is the result
Drawing a line under the review of methods, I want to warn readers against possible mistakes. Remember that there is no universal method suitable for absolutely everyone, in principle! What worked in a film greenhouse may not be effective in a glass one. Volume, tightness and even humidity — everything is important, everything needs to be taken into account. The only safe way I see: first, testing the method in specific conditions, and only then — planting seedlings.