One of the most ignored and probably less talked about topic in the domain of greenhouse gardening is the flooring. While most of the emphasis is on the soil in which the plants are grown, the type of flooring that is suitable for a greenhouse is equally important.
There are quite a few greenhouse flooring solutions that you can try out in your greenhouse. But by experience, using a dirt floor is probably not the best way to go about it even though it might seem an obvious choice.
For instance, watering of plants and condensation inside the greenhouse can lead to a muddy mess which can cause the growth of weeds, disease, and unwanted pests.
So how do you choose the right flooring for your greenhouse?
As I mentioned earlier, there are plenty of inexpensive and easy to install greenhouse flooring solutions that you can install yourself. And there’s no special science involved in that. Any water-permeable surface that can be used for a patio or a walk-way can be used for your greenhouse floor. This is important to handle the excess water from irrigation.
Also, you must keep in mind here that flooring essentially means the pathways where the plants are not grown. So even if you’re growing the plants directly and not in pots, the soil will not be considered as a floor in this case.
Another factor to be considered while choosing the flooring for your greenhouse is the cost involved. Some flooring options like concrete and wooden flooring can cost more than say for example pea stone or mulch. Hence if you are a small greenhouse owner, choose a greenhouse flooring solution as per your budget.
Building the base for flooring
For long-term stability, improved drainage, and a level floor surface, I’d recommend setting up a 4 to 6-inch subbase of compact gravel stones before starting your greenhouse floor. The topsoil and subsoil must be removed before filling in the subbase.
Another thing you need to do is install a layer of weed barrier which will separate drainage material from the subsoil. This will also help keep the weeds from growing into the soil below.
This weed barrier needs to be perforated so that water can percolate through. Sourcing the weed barrier is no big task. You can get it from most garden centers and greenhouse suppliers. Above the weed barrier, you need to fill the area with gravel or small stone, leaving a lot of space for the floor material. This flooring material can either be filled in all of the ground surfaces including the pathways and under the benches or only in the pathways.
Type of Greenhouse Flooring Solutions
Once the base for the flooring is built, you can choose the flooring based on your requirements and the layout of your greenhouse. More often than not, what works for someone else might not work for you as every greenhouse has its own plan and purpose.
As i have mentioned earlier, we will not be considering the soil flooring here as not only does it get messy, there are chances of unwanted weeds growing on a soil floor.
Following are some flooring ideas for your greenhouse and pathways:
- Peastone and trap rock
They are the starting level as far as the flooring is concerned. They do not cost a lot. They also provide good drainage, a factor that is much needed in greenhouse flooring.
Pea stone also helps in retaining heat during the colder months. They are also relatively weed free if you consider the experience of greenhouse owners with a pea gravel flooring.
However, their durability is also in question and over time they may be dislodged and require reshaping.
2. Bricks and Patio Blocks
Bricks are available in a variety of colors and textures. They can add an aesthetic look to the floor because of the interesting patterns that can be created by laying them. They might cost a bit, but one way to address that is by using used bricks.
When you use bricks for the flooring, you need to ensure that they are coarse. Avoid glazed bricks even though they look good as they can become slippery when wet or covered with algae. You don’t want that to happen. Bricks in their natural form will absorb any water that would have spilled.
Before installing the bricks, put in place a compacted base of sand or stone dust underneath. This will keep the surface level and will avoid any raised surfaces. This will also ensure good drainage.
Another option is to use patio blocks. They are available in square, rectangular, or even decorative shapes. You can design a pattern on paper before buying the material. Just like with bricks, put in place a compacted base of sand or stone dust underneath.
3. Flagstone
Flagstone is mined from quarries and is available in rectangular or random shapes. It is a hard stone and has uniform internal layers and hence can be cut into smaller stones of varying thickness.
Ideally, you should use a minimum thickness of 1 inch to prevent shifting of the stone once it has been installed. Again with this flooring, you need a compacted base. Areas between stones can be filled with sand or stone
4. Concrete
You can place concrete in the walkways or over the whole surface. For strength, it is recommended you use a thickness of atleast 4 inches. Ensure that you brush the surface so that slipping is prevented.
If you are installing the flooring for a home greenhouse (requiring 2 cubic yards), it might be difficult to obtain the concrete from concrete suppliers as they usually supply in trucks that carry 7 cubic yards or more. Some contractors in the countryside have on-site mixers that can provide you with the quantity you need.
Alternatively, you can rent a power mixer to mix your own concrete. Here’s what you need to prepare a mix that will give you a sturdy, watertight floor – one part cement, 2 1⁄2 parts sand, and 3 1⁄2 parts 1⁄2-inch to 1-inch stone by volume. Add just enough water so that the mix is viscous enough and flows without it turning “soupy”. A thin mix will lack the strength to hold tight. For an aesthetic look, you can lay unglazed ceramic tiles on top of the concrete once it dries up.
Keep in mind to install a floor drain if you install concrete over the entire floor surface. This will allow the removal of excess water. The floor should be sloped towards the drain and the drain should be equipped to collect soil and other solids in its settling basin.
5. Wooden Floor
Another alternative is to use decay-resistant or pressure-treated wood. Use lumber boards of 2×6 or 2×8 and atleast allow 1/6 to 1/8 inch space between the boards for water to drain. However, it is prudent to use this type of flooring only in the walkways, as frequent wetting of the wood can damage it over a period of time.
Another method is to first set the base made of cardboard boxes opened up and then cover it with a layer of wood chips or mulch that you can easily get from the local city dump yard. The mulch can hold the heat and the moisture in the floor. It also helps to keep the grass down which can otherwise grow up to 12 inches tall! However, you need to regularly maintain it to keep it free from mold and spores.
As explained earlier, the type of flooring you choose will depend upon your budget as well as the size and scope of your greenhouse.
Do you use any other flooring options for your greenhouse? Do let us know in the comments!