Building a Polyfilm Greenhouse? Not sure how to attach the film to your greenhouse frame? This video discusses the use of batten tape or base and wiggle wire systems. They are both excellent for wood frames. The wiggle wire system is good for metal frames as well. As always, we hope you find this edition of “The Greenhouse Minute” informative and helpful.
Of course the answer to this question is yes, you do need ventilation for your greenhouse. But what if your greenhouse is in a location with no electricity? There are several options which will alleviate this problem. The simplest thing to add is roof vents or side vents. A lot of the greenhouse kits will come with these either as standard equipment or as an option. If you are building your own greenhouse, you would just frame them out using the same material as your greenhouse and cover them with the same material as well. To simplify matters even more, I recommend using solar powered openers with these. This is an arm that is operated by a wax cylinder. It is a pretty basic piece of equipment. It functions on the principles of contraction and expansion. When it is warm the wax will expand and cause the arm to open. When it is cool the wax will contract and cause the arm to pull shut. There is no exact temperature setting on these, but there is a thumbscrew at the end which can be used to adjust the opening and closing temperatures. They are typically able to open between 65 and 75 degrees F, depending on the manufacturer. They will definitely simplify your life during the spring and fall months. No more getting up in the morning and opening them before you head out to work. Then, if you get home and forget to close them at night, the results could be devastating.
If you are building your own greenhouse, or need ventilation in an existing greenhouse, our solar powered shutters are perfect. They will supply natural ventilation for your greenhouse. They come in 6 sizes and require no electricity. The 4 smaller sizes may be fitted into a polyfilm greenhouse without any further framing. Or, they may be installed in a framed out opening the same as the 2 larger sizes. These shutters are perfect for just about any outbuilding, not just for greenhouses.
A final suggestion for natural ventilation is roll up side curtains. These are typically found in polyfilm greenhouses only, and come with a manual hand crank.
In conclusion, not having electricity in an area where you want to put your greenhouse should not be a deterrent. Use any of these systems, or any combination of these systems to help ventilate your greenhouse. Also, if you don’t like any of these suggestions, another way to go with this is to use solar panels to supply electricity to your motorized ventilation systems.
We put so much time into planning out our greenhouses — glazing options, size, lighting, bench/table configurations, even décor. But sometimes, we forget to consider one of the most basic elements of the greenhouse, the floor. There are many options for flooring material, ranging in cost from quite inexpensive to fairly costly, but every greenhouse floor must start with positive drainage. With all of the misting and watering that occurs daily, the last thing you want is to create a soggy, slick basis for walking and working. So start with good drainage and take that into account as you are making your flooring decisions, then check out these options to determine which one fits your budget, aesthetic and lifestyle.
Although pouring a concrete slab is likely one of the more expensive flooring options, it creates a permanent, solid basis for your greenhouse activities. Much like a patio floor, a concrete greenhouse floor will need to have a surface drain installed to allow water to drain out. Pouring a concrete floor is not an easy DIY project as there are too many variables to cover, so this is an option best left to the pros. The investment will repay you many times over, though.
Similar to the concrete slab, stone flooring is a more permanent option, especially when mortared in place. If you opt to forego mortaring, space the stone closer together and use a stabilizer in between such as decomposed granite or gravel. Make sure you choose a stone that has a flatter, smooth surface, as you don’t want to be tripping as you work — look for larger, flatter pieces labeled “flagstone” or “patio stone,” and forego lesser expensive “field stone” that tends to have a bumpy, irregular surface. A surface drain is also a must if you opt for a mortared stone floor.
Brick flooring is a beautiful, elegant and permanent option, but it can also be a more expensive one. Brick, like stone, does not necessarily need to be mortared in place, but it will need a surface drain if it is. If your greenhouse location has relatively level ground, and you have some basic DIY skills, this could be a project for you to take on, but most greenhouse owners will want to consider hiring the pros to correctly install this floor.
Many greenhouse owners opt for pea gravel for their flooring. It’s inexpensive, creates positive drainage and is readily available. You can also opt to install weed barrier underneath the gravel, and option that I recommend to keep the gravel from settling into the soil and disappearing. Be sure to keep the gravel clean by periodically washing it down, as a build-up of moisture can create a slick surface. As easy DIY project, gravel is a great middle-of-the-road approach to creating a functional greenhouse floor.
Also known as weed barrier, this woven black fabric is the choice of many commercial greenhouses to suppress weeds and create a nice level floor for walking and working. It allows water to pass through, creating positive drainage, while at the same time keeping your floor from becoming muddy. If you choose this option, go for the more expensive, commercial grade fabric, as it truly is a more durable and effective product. As with most things in life, you get what you pay for — and why go to the trouble of installing this product if it’s not going to do the job?
Good old-fashioned mulch is a great option for greenhouse floors — it provides great drainage, sure footing and enriches the soil as it breaks down. It’s also readily available and inexpensive. Opt for a higher quality shredded mulch rather than wood chips, as shredded mulch interlocks to form a tighter mat upon which to walk. You’ll need to replenish your mulch floor as it breaks down, but it’s an easy annual task that any homeowner can do. It’s available both in bags as well as in bulk (per cubic yard), with the bulk option being the least expensive by far.
It seems to me that a lot of people struggle with the decision on which shade cloth is best for their greenhouse. I think they are way over complicating the issue. A greenhouse shade cloth is pretty much like stepping under a shade tree in the summer. You have felt the cooling pretty much right away when you do this. A shade cloth does pretty much the same thing. There are several different choices of material, but the differences are pretty basic. The woven shade cloth is the least expensive. It is a black color. It must be taped on the edges, or it will ravel. It is best used on the outside of the greenhouse. The next choice is a woven shade cloth. This will be intermediate in pricing. It is really nice, as it has some stretch and will not ravel, so the taping is not a necessity with this type. Although we do tape all of our edges so we can add grommets for simple installation. I personally prefer to use this with a greenhouse with automatic roof vents. The way we have always done it is to put the shade cloth on tight on the ends. As we near the vents, we don’t fasten the shade down as tight. We will go back for the next 3 or 4 days and adjust as needed. You want to make sure that there is no strain on the vents when they are trying to open. The next choice is the reflective shade cloth. This is the most expensive, but it is a good choice to use on the inside of a greenhouse. A lot of commercial growers like this for exterior applications as well. Probably the most common question I get is – what percentage should I use? The higher the percent, the more shade you will get. I have found through the years that a lot of orchid growers will prefer a 50% shade cloth. For general purpose growing, ie vegetables, annuals, etc, a 60% to 70% shade is typically used.
I received a really nice email from a gentleman the other day who had read one of my previous articles regarding greenhouse accessories. He pointed out to me that he did not use the accessories in exactly the same way as I outline in my article. This just served as a reminder to me that greenhouse growing is indeed a learning curve for all of us. Here’s the thing – We all live in different climates. We are all growing different plants. It is up to us as greenhouse owners to learn how to supply the necessary climate in the area we live in. He mentioned that he only used his heater at night in his location. I would dare to say that someone in Wisconsin growing tomatoes in the winter would totally disagree with this. He also mentioned an evaporative cooling system. He was in a location with a desert type climate. I can see where that would work for him. But here, in Louisiana we have just about 100% humidity (I am sure it just feels that way) all summer long. An evaporative cooling system is totally ineffective here. He also considered a shade cloth as an optional accessory. I consider it an absolute necessity. That is, if you are using your greenhouse at any time except in the winter months. If you have it shut down in the spring, summer and fall, I would not really suggest getting one. When someone calls me asking about greenhouses and accessories, I recommend that they at least get a ventilation system at the same time, as it is installed into the greenhouse frame. This is easier as an initial installation than it is as a retrofit. I don’t like loading greenhouses up with a whole lot of equipment that you may not need at a later time. I suggest adding additional accessories one at a time and as the need arises. Of course don’t wait for the last minute, because everyone else will be in need at the same time. For custom made items such as a shade cloth, this can lead to a delayed lead time. The thing is, we are buying a greenhouse maybe for practical reasons, but most of us are purchasing them for our love of growing. So relax, take the time, learn what you need in your area, for your plants to make your greenhouse a success. And as always, keep growing!