The extension of the season

 In Quebec, the growing season is short, which leaves little time for several cultures' market gardens to reach their full potential. The job of a market gardener is therefore to find solutions that make it possible to modify the growing conditions in his gardens in order to protect their crops from frost and cold. When he is a question of prolonging the season, it is necessary to specify that I am not talking about greenhouse production where heating is provided to the crops, but rather simple techniques and technologies, economic which allow crops to be "forced" and protected against bad weather.


This idea is not new, but it involves generally the heating of greenhouses. The weak fuel costs over the past 50 years seem to have made us forget the advantages of a “low-tech” approach. In the northeastern United States and in other regions where the demand for products premises is very strong, several small market gardeners today strive to find solutions energy efficient to harvest more early and extend their season into winter. These innovations are exciting to follow and better and better documented. The leader of this movement is Eliot Coleman, whose ideas and techniques demonstrate how to push the limits of seasonal cycles by combining plant biology and simple shelters. To see her seen with my own eyes in different places, I can assure you that many cultures can be harvested year-round, with simple means, even when winter conditions resemble those in Quebec. For those interested in these ideas, there is a whole literature on the subject.


As for us, we have for the moment dismissed the idea of ​​being in production during all winter months. As I just mentioned, it is not technical reasons that have slowed down our enthusiasm, but rather the fact that these months offer free time that we take and appreciate a lot. That said, we still force our crops, especially in the spring. Over time we came to the conclusion that people's enthusiasm for a vegetable peaks at the beginning of summer and our goal is to maximize the June harvests. Set to share our greenhouse of tomatoes that we do not hesitate not to heat, the methods we use are all passive. In any case, not only are the harvests earlier but the crop quality and yield are improved. This is, I believe, the biggest reason to adopt these techniques.


Floating blankets and mini-tunnels

Floating blankets are, in my opinion, one of the greatest technological innovations of the horticultural industry. These tarpaulins (many people call them that way, in the middle) are webs of non-woven polymer fibers, a material that allows air and water to penetrate while acting as a physical barrier against wind and pests. When the house of crops, floating covers increase soil temperature while helping to maintain humidity. In doing so, they provide some additional degrees of frost protection. Their placement, just after sowing in the ground or transplanting, accelerates germination and/or protects young plants from bad weather like driving rain, strong winds, and hail. In short, these canvases allow you to recreate anywhere in the garden a microclimate comparable to that of a tunnel.


There are blankets of different thicknesses on the market (expressed in grams per meter square). Thicker fabrics will have a better thermal capacity but will pass less than light. It is, therefore, necessary to make a choice of material depending on the situation. In our gardens, both in spring and in autumn, we use floating covers of 17 or 19 grams / square meter which are a good compromise between durability (when handled with care, they can be stored for more than one season) and light infiltration (a decrease approximately 15%). We also use canvases of a thickness doubled as a heat shield for shelter crops during freezing nights.


In spring, the floating covers cover all of our production. For seedlings in the ground, we place them directly on the ground by leaving a slight detachment which allows the foliage crops to grow under the canvas. For crops that are transplanted and more fragile, we support the floating blankets with hoops made from # 9 gauge galvanized steel merchant wire.


For broccoli, zucchini, and other crops that form tall plant covers, we use larger arches, formed of ducts electric PVC 16 millimeters (1/2 ") in diameter and 2.45 meters (8 ') long. We space these poles every 1.5 meters (5') or 3 meters (10 ') staggered when several adjacent planks are covered by the same blanket floating. In order to properly fix these poles, we sink into the ground about 25 centimeters (6 "),

in a hole dug with a stake.


Finally, we use other hoops for this which we call mini-tunnels. These latter are particularly useful in times when snow accumulations are possible. They are made with galvanized metal ducts found at the local hardware store and are folded using a pipe bender. These hoops are more expensive to manufacture but strong enough to withstand heavy loads. At the beginning of spring or towards the end of autumn, we cover our mini-tunnels in transparent polythene. So, they offer practically the same advantages as a tunnel, but at a fraction of the cost.


To keep floating blankets firmly anchored, we cover their sides or use bags of rocks placed at the foot of the arches. So that they keep for a long time, these bags must be treated UV rays, a worthwhile investment hardly. When laying floating covers, it is important to make sure to stretch them sufficiently in order to prevent the wind from beating the canvas on the crops when it is strong. Unfortunately on our windy site, in the spring the anchoring of the floating covers is continually susceptible to undo. The only solution we have found to this problem is to patrol regularly in the gardens to check the condition of the anchors.


When we don't need the blankets anymore floating, we store them in sacks of grain, which we label according to the width and the condition of the cover. At the end of the season, one of our final tasks is to try to fix the covers with holes using adhesive tape UV treated designed for this purpose. Most of our blankets last about three years.