Hoop house

 Another option is crawler tunnels very interesting to extend the season. A caterpillar is a simple tunnel and cheap which has the advantage of being mobile. As these structures rise and fall disassemble easily, they can be carried anywhere in the garden at any time of the season. We use ours for force direct sowing of carrots and beets, then we move them to cover the nightshades, who always need extra heat in summer.

To build a caterpillar, several techniques and materials can be used. Most simply do not require anything other than PVC, reinforced concrete bars, and rope. We made ours with PVC pipes from 4 millimeters (1.5 ") by 6.1 meters (20 ') in length (two pieces well glued with a union). The arches are spaced 3.5 meters (10 ') apart and anchored to the ground by inserting them into 61 cm (24 ") steel rods, half planted in the ground. reinforce the structure, a cable connects each arch to its gable and is attached to a post firmly planted at both ends of the caterpillar.

The polythene which covers the structure is held to the ground by covering one of its sides with earth and using bags of rocks on the other side. Anchored ropes on the ground and passed from one edge to the other between each arch then secure the polythene against strong winds, giving it the appearance of the caterpillar. To ventilate, we open the tunnel by rolling the polythene and keeping it in place using hooks attached to every two arches.

In 2005, we spent approximately $ 400 of materials, excluding used polythene, to make a track covering a space of 3.65 meters X 30 meters (12 'x 100'). If we consider that the tunnel thus covers two planks and that it is de - placed three times in the season, this represents an investment of $ 0.33 / square foot to cover six boards: we're getting an excellent deal. The only disadvantage of crawler tunnels is that their structure is not very high, which complicates the work in a standing position. In addition, you have to constantly bend down to get in and out.

Permanent tunnels

A tunnel is a permanent structure made of semi-circular steel arches, bolted and covered with a polythene film. Unlike a greenhouse, tunnels are fairly low structures, of construction simple and mostly unheated. The tunnels I'm talking about are also different from large popular tunnels for market gardening on a great surface. In general, their width is 5 or 6 meters (16 'and 20') and their height at pinion does not exceed 3 meters (10 '). A tunnel can be of any length and can be lengthened with the addition of new sections, which is particularly interesting in the context of the start-up.

One of the great advantages of a tunnel is that it is a shelter that can be used year-round. This shelter can therefore be used for early crops and late before and after a demanding summer crop in heat. Sown at the right time, vegetables resistant to cold, such as spinach and other Asian greens, can be harvested despite the periods of frost and allow production to be extended by several weeks. There are many tunnel models and most suppliers of greenhouse structures also sell them. As the cost of a new structure is sometimes high (the metal price seems to increase every year), several small producers decide to manufacture their tunnels by bending steel tubes using a metal bender. In my opinion, however, the best strategy to reduce the cost of this investment is to seek a structure of the used tunnel. Although they often have to be taken apart and provide adequate transport, the game is worth its candle. But anyway, buying a tunnel is one of the best investments you can make. Can do. Crops produced inside these shelters recover costs in a few seasons, if not the first.

The tunnels are permanent installations; it is, therefore, important to plan their location well. Special attention must also be granted to good soil drainage under the tunnel, otherwise, the crop beds may remain wet too long in the spring. Put down leveling the land, which requires work heavy in gardens, installing agricultural drains around the perimeter of the structure is the best solution to this problem. Ours have side openings (roll-up) and large sliding doors. front and rear, which is sufficient in terms of ventilation.