The layout of the greenhouse was the best I could come up with that fit all the needs I had for the space. This included being able to:
- root cuttings,
- start seeds and
- bring them along in a protected environment,
- protect plants in winter that are either tender or dislike winter moisture,
- grow tomatoes and other special vegetables. We cannot naturally grow tomatoes here because we do not have enough heat in summer.
While the greenhouse is fairly small (approximately 9’x11′), I think I managed to satisfy all of the goals, although there is no such thing as a greenhouse that is too large. We always manage to fill all available space plus 25%.
The most complex of the needs is to root cuttings. This requires both bottom heat and mist to stop them desiccating while rooting. I dedicated about 3′ x 3′ for this task and constructed what is essentially a box at bench height. It has cedar sides and a plywood bottom. It is reinforced underneath. First in goes a couple of inches of insulation. You don’t want heat escaping out of the bottom. The box is lined with plastic, and filled with about 1″ of a sand/peat mixture.
On top of this is a heating cable with built in thermostat. Make sure that the cable does not cross itself and try to get even coverage. This also required drilling a hole through the cedar and through the plastic insert. Once this is in position, another 1 ½” of sand/peat mixture was spread on top. Many people talk about using pure sand, but I also read that adding some peat enables it to more evenly hold moisture which conducts the heat better. You don’t want it dripping, but sand can dry out very easily. I have been happy with the results.
Now, you just plug the heating cable in and let it do its thing. It keeps the soil at around 70F. It would have been nice to have been able to change that, but in reality, I have found this to be very workable.
The remainder of that side of the greenhouse is a lath top. Lath is a thin strip (5/16″ thick, 1 ½” wide and 4′ long) of straight grained wood which used to be used for plaster walls. I find it works well for bench tops. It is cheap and I use a preservative on them to help prolong their life. I space them the thickness of the lath apart. That makes it easy to get consistent installation.
The next job is to add mist. There are several pieces to this. In order they are:
- Solenoid that controls the water flow into the pipe,
- Pipe and mister nozzles,
- Zone control/separation.
Before anything else there is a water filter. The dimensions of the mister jets are tiny, and you do not want them getting clogged. Neither do you want any debris getting stuck in the solenoid. The solenoid itself is a little different than the ones used for garden irrigation. Most of them tend to be made of brass and operate off 110V. Here is an example of the type of solenoid I used. The control for this is discussed in another posting.
A flexible hose is used to connect this to the mist line. You will notice the pipe goes along the bench and there is also a pipe that head vertically down. This is the drain. Greenhouses are hot and when water is allowed to remain in the lines it grows algae. The auto drain at the bottom of this pipe releases as soon as the pressure drops. The mist line is slightly inclined up as it goes along the greenhouse ensuring that all water drains away. I do not waste that water – there is a bucket underneath that catches it and I use that for general watering purposes.
The 1/2″ supply pipe is suspended from the rafters. Mist nozzles are at approximately 2′ spacing. I used special PVC pipe with a threaded hole for the mist nozzle. That means I can replace the nozzles if necessary or change the mist rate by putting in ones with a different hole size. At the end of the main bench, I put a shut off valve and a screw thread. This is so I can either have mist on the end bench or turn that off when not needed.
I may need to make a modification and put a T over the heated area. This area needs slightly better coverage than it has now, especially towards the window. I could put shade cloth up, but I like to push them closer to the window once I know they have some root, but are not yet ready to be potted up.
Opposite the propagation bench is the preparation bench. This has a couple of small lath areas at each end, but the two most important elements are the work surface and the sink. The sink is a deep tub that is large enough to accommodate my soil bins. The work surface is an offcut of granite that was left over from a kitchen project. This provides a stable, easy clean surface. While a solid color may have been better, it was free and very fit for purpose. There is no mist on this side of the greenhouse because nothing is intended to stay here.
Above the preparation area is a stainless-steel shelf on which I keep various thing, such as tools, hormone powder, fertilizers etc. Pots get stacked along the windowsill, ready to be used. Under the bench are storage tubs that either contain raw ingredients for potting mixes, such as sand, perlite, compost, peat etc, or mixes that I have already made up.
One final, but important element, is the concrete mixing tub mounted below the lath area on the right and part of the preparation surface. This is just held in place by a couple of strips of wood and can be easily pulled out or hidden under the bench. This is where are the mess gets swept into, and I keep a small brush on the leg for just that purpose.
The end of the greenhouse is reconfigurable. These benches can be removed, enabling plants to be grown right in the exposed soil. This is what I use for growing tomatoes, peppers and other things that need help with ripening. While good in theory, the areas on each side are not easily accessible one the plants have filled in, and so a lot of crop was getting lost because I could not pick it easily. Next year, I will probably only remove the middle section – still enough room for one tomato plant and some basil. Alternatively, I could put a stepping stone in the middle that would allow me to reach to each side better and sacrifice some planting area in the middle. We shall what happens next year.
Well, that is my green house setup. I would love to hear about you have done with yours.