Table of contents:
- 1. Find the optimal location
- 2. Plan and foundation
- 3. Building material for the greenhouse
- 4. Plan the substructure
- 5. The greenhouse glazing
- 6. Build the frame structure for the greenhouse
- 7. Prepare plexiglass plates
- 8. Insert the plexiglass walls in the greenhouse
- 9. A roof for the greenhouse
- The cost of the self-made greenhouse
Video: Build your own greenhouse - building instructions, costs, location
A greenhouse really spices up the garden and extends the gardening season. So what are you waiting for? Of course you can buy a finished one in stores. Just as cheap, but higher quality: a self-made copy. We explain step by step how you can build your own greenhouse. After all, tomatoes, peppers and the like from their own greenhouse taste much better than supermarket vegetables.
1. Find the optimal location
Where should the greenhouse be so that it gets as much sun and heat as possible all year round? Generally, a south orientation is recommended, a north orientation is not.
However, also note whether the greenhouse could be in the shadow of the surrounding buildings. Especially in the winter months when the sun is low in the sky. A very good way to check the course of the sun for the intended location for different seasons is the website sonnengeschichte.de. There you can easily get an overview of whether the target space for your greenhouse is ideal for all seasons.
2. Plan and foundation
When planning, we follow the bed width of 3 meters specified in the allotment. Our 3 x 1.5 meter greenhouse fits in any garden and can also be set up in a home garden. You can easily adjust the size to your own garden. In detail, we decided on the following greenhouse construction:
- A wooden frame will form the body of the greenhouse. We use wood for the frame because it is easy to work with existing tools.
- We use plexiglass multi-wall sheets as walls and doors. These plates should ensure that as much light as possible gets inside. Although they are a little more expensive, they hardly yellow. And the multi-wall sheets made of plexiglass are provided with a coating that allows the water to drain off easily.
- The roof is covered with corrugated sheets. The corrugated sheets on the roof are also coated and let a lot of light through.
- Of course, the greenhouse needs a safe and stable surface. Sure, a foundation can be poured from concrete. Only advisable if the greenhouse should really find its place permanently in one place. We built a ring foundation from lawn edging stones, but placed the stones with the curve downwards, i.e. in the ground.
When it comes to the foundation, we make it easy for ourselves and simply put lawn edging stones in the opposite direction into the earth.
Photo: Don Medien GmbH
3. Building material for the greenhouse
|8 plexiglass multi-wall sheets (Alltop)||1500 x 980 x 16|
|3 plexiglass corrugated sheets (resist)||1050 x 1045 x 1.8|
|2 bars||2900 x 55 x 55|
|4 bars||1450 x 55 x 55|
|4 bars||1400 x 55 x 55|
|10 bars||930 x 55 x 55|
|1 bar||2900 x 65 x 25|
|1 bar||2900 x 30 x 15|
|8 strips||1500 x 65 x 25|
|4 strips||1500 x 15 x 15|
|2 strips||1500 x 30 x 15|
|32 heavy duty bracket|
|32 aluminum tube spacers||20x10|
|3 aluminum rails about 600 millimeters long
or wooden rails for recording
of the front multi-wall sheets
|Long wood screws with washers|
|Short wood screws for the angles|
|14 special screws with washers
for the corrugated sheets
4. Plan the substructure
For the supporting frame you need planed wooden slats in a stable size. These are painted with a colorless wood protection glaze and the beams are screwed together at angles.
|Use stable beams at least 5 by 5 centimeters.|
|Use torsion-free, planed wood, i.e. well dried solid wood or glued wood. Larch wood is ideal (high strength). This is important so that later there is no tension in the wood that could damage the Plexiglas multi-wall sheets used for glazing.|
|The wood should be impregnated once or twice before processing and painted with a clear wood protection glaze. Let the paint dry well and air dry. Attention: There are colors whose ingredients are not compatible with plexiglass panels. If you want to process plexiglass, you should definitely check the compatibility before buying the color|
|Heavy-duty angles are optimal for a stable connection because they are particularly stable. Pay attention to the correct head for the screws: Round-head screws fit the angles, they lie firmly on the metal.|
5. The greenhouse glazing
For the glazing of the self-made greenhouse, you should use multi-wall sheets made of plexiglass. Most garden greenhouses are built with inexpensive multi-wall sheets made of polystyrene, PVC or polycarbonate, which is why they are usually quickly yellowed and embrittled, and after a while hardly let any light through. Unfavorable! Many kits from the hardware store also use such panels in order to be particularly inexpensive. When glazing, you should note the following points:
- The greenhouse should let a lot of light through to the plants. With a light transmittance of 92 to 94 percent, plexiglass panels are more translucent than glass. In contrast to the other multi-wall sheets, plexiglass sheets are UV-resistant and therefore cannot yellow. Often, these plates come with a 30-year guarantee from the manufacturer.
- Choose plexiglass panels with a coating that allows the water to drain off easily and the panels remain clear and translucent. So the cleaning effort is limited.
- Surely you want to build a long-lasting greenhouse in which tomatoes or cucumbers can ripen for many years. Therefore choose unbreakable and hail-resistant multi-skin sheets. Although these are a little more expensive, they are definitely worth the money.
- In addition, the multi-wall sheets are closed at the top and bottom with aluminum rails so that no water runs into the glazing.
Glazing tip: getting plexiglass at a hardware store is sometimes not that easy. The stock polycarbonate or PVC sheets are usually sold there. If you want plexiglass, you have to ask explicitly! In many cases, these can be ordered from the catalog at the hardware store (Hornbach, Bauhaus, etc.) - or they can be sent to one of the specialist dealers who also delivers the panels in a tailored manner.
6. Build the frame structure for the greenhouse
The woods that we bought in the hardware store are now screwed together into four frames. We pre-assemble the four side parts and then want to screw them together on the foundation. You can find a detailed construction plan with the individual parts here.
|Cross-cut saw, circular saw or jigsaw for cutting the beams|
|Powerful cordless screwdriver for screwing|
|Circular saw with a fine or special saw blade for plexiglass|
|PUK saw for cutting the aluminum U profiles to length (but can also be cut to size in the hardware store)|
|Round-head and Spax screws for the angles and strips|
The individual steps for greenhouse construction:
- The front and rear frames each consist of two 3-meter long crossbeams and two longitudinal beams. This creates 0.98 meter wide fields for the multi-skin sheets. We chose these dimensions so that we do not have any waste with 0.98 x 3 meter base plates. The best way to cut the wood with a chop saw is to get a smooth surface at a 90 degree angle. Attention: The rear frame is 5 centimeters lower, so that we get a roof slope and later the water can easily drain from the roof.
- The side frames are each 1 meter wide and here, too, the front longitudinal strut is 5 centimeters higher than the rear.
- At the front, the plexiglass panels should be removable so that it doesn't get too warm in the greenhouse in summer. That is why we mount two 15 x 15 millimeter strips on the upper crossbeam and a 68 x 26 millimeter wide board on top, which should serve as a guide for the panels. On the lower crossbeam there are three narrow rails 30 millimeters wide.
- Before screwing together, you should paint the woods with a colorless wood glaze. It is best to use water-based glazes here.
- First put the frame for the rear wall on the foundation, align it and screw it to the two side parts. Tip: Before two frame parts are screwed together, we fix them with a screw clamp and can then easily align them and connect and fasten them using angles and Spax screws.
- In the last step, screw the front part together.
Screw the individual wooden frames together with angles. The clamp helps with assembly and alignment.
Photo: Don Medien GmbH
Important: connection to the foundation. To make the self-made greenhouse storm-proof, it must be firmly connected to the heavy foundation made of lawn edging stones. To do this, we screwed two small metal plates to the stones. We connect these to the wooden frame - and the greenhouse can withstand a violent autumn storm.
Photo: Don Medien GmbH
7. Prepare plexiglass plates
The multi-skin sheets are 16 millimeters thick and open at the top and bottom. To prevent dirt and moisture from entering, the panels must be closed with U-profiles. Professional systems can be used for this, which then usually ensure that condensation water runs off on the underside of the plexiglass plates. If you want to do as much as possible yourself, you can have simple aluminum U-profiles cut to length in the hardware store and use them. Each chamber is drilled with a four millimeter hole through which the condensation water can run off. You can simply clip this profile onto the plexiglass plates. Basically the following applies: As dense as possible at the top, as dense as necessary below!
The plexiglass used can easily be cut with a jigsaw or circular saw. It is best to use a special plastic saw blade. This is particularly multi-toothed and ensures a clean cut. Important: Apply as little pressure as possible on the saw, then the cut will be clean and straight.
8. Insert the plexiglass walls in the greenhouse
In the last step you should mount the wooden frame on the foundation. The plexiglass web panels are now inserted into these frames: three panels next to each other on the back, one panel cut to the left and right, and three panels are only hung as doors at the front. Important: Do not drill through the plexiglass plates, just clamp them on! It must not be a rigid connection, the plates need space to expand or contract depending on the temperature. That is why we screwed a strip of the thickness of the panels (15 millimeters) onto the load-bearing wooden beams. Now a narrow board is placed on this bar, which then presses the board onto the wooden beam. So that the multi-wall sheets are not pressed too hard, you should saw off short pieces of an aluminum tube and place them in between as spacers. The screws push the tube into the wood and therefore cannot be screwed on too tight. All in all, a plate needs about 1, 000 millimeters of space: the plate has 980 millimeters and we need the 20 millimeters for the expansion and the spacer sleeves.
The plexiglass panels are not drilled through and screwed directly to the wooden structure, but clamped with strips. A thin aluminum tube ensures the correct distance.
Photo: Don Medien GmbH / Jörg Wulf
In the front, simply insert the plexiglass web plates into the guide rail without screwing them in properly. These plates can then be removed in summer and thus regulate the temperature in the greenhouse. The protective film is only removed from the plexiglass when all the panels have been inserted: it protects the all-top coating during work, which will later ensure that the rainwater runs off without residue.
9. A roof for the greenhouse
You can use plexiglass corrugated sheets as the roof. They are fastened with special system screws, each of which is supplied with the pressure plate and seal. The protrusion on all sides reduces the direct irrigation of wood and plexiglass panels. Of course, you can also use the plexiglass slats on the roof - then even more heat is stored inside. Good for spring, but rather problematic in summer.
We use corrugated sheets made of plexiglass as roof, which are connected with system screws.
Photo: Don Medien GmbH
The cost of the self-made greenhouse
Admittedly, the whole thing is not cheap! The wood, the screws and angles only make up the smaller part: a maximum of 200 to 250 euros should be estimated for this, the more expensive are the plexiglass panes, for which you have to calculate around 150 euros per piece. This is of course much more than with normal multi-wall sheets. But: If you want to work seriously with the greenhouse and get a decent harvest, it is definitely worth it.
A wide variety of plants, flowers and herbs can be found in a greenhouse.
/ DUSAN ZIDAR