GROWING FOOD IN THE GREENHOUSE
The greenhouse at Good News Ranch has kept us supplied with year-round vegetables since 2017. During our winters the greenhouse provides us with lettuce, spinach, chard, bok choy, broccoli, cauliflower, cabbage and zucchini. We enjoy fresh tomatoes year-round from the greenhouse. I’ve also occasionally harvested turnips, rutabagas, beets, daikon radish, kohlrabi, & Chinese cabbage. Herbs growing are thyme, rosemary, cilantro and basil. Summers provide us with tomatoes, peppers, cucumbers and sometimes winter squash all in the greenhouse, while everything else is grown in the outdoor garden. Please see the blog post, “Garden Planning & Implementation” to read more about our greenhouse construction.
GREENHOUSE SOIL
Our greenhouse beds are raised atop a concrete floor, and reach about 28″ in height. The soil we created at first (2017) was a combination of compost (we purchased from a garden center), manure, peat moss, leaves and perlite. Since then it has matured from the addition of vermicompost & its worms, various nutrients & fertilizers, & garden compost. Each time plants are removed and new ones replace them, the area is refreshed with garden compost, vermicompost & fertilizers.
Since our greenhouse is used year-round, we have quite a turnover of plants! (See “Planning” below.) In order to refresh the soil, we occasionally will grow a cover crop in these beds. I call them “baby covers” since they only grow to about 3-4″ tall before they are tilled into the soil. See the “Cover Crops” page for more details.
GREENHOUSE WARMTH
For the month of January 2018, the greenhouse temperatures averaged 74°F during the day, and 56°F overnight. (The outdoor temps ranged from -9 to +62, averaging 11 at night and 48 during the day that month.) At first, we had been installing insulation over the glazing each night to retain the heat that had been collected during the day, but decided that was unnecessary. Now, we only do this when it is extremely cold. The floor and soil in the beds are heated from the sun during the day, and the soil stays at about 65-70°F. The pond (shown at left) is filled with water to act as mass thermal storage. We are now using a radiator heating unit that draws its heat from the water heated by our solar collector. We have a small, on-demand propane water heater which heats the water when the sun doesn’t shine and the solar collector storage tank has run out of hot water. These are all automated to turn on and off as needed.
GREENHOUSE PLANNING
A lot of planning goes into the Greenhouse. I’m continually planting & replanting & letting small areas rest between plantings. I’ve learned to plan ahead by guessing how long plants will be in their spots, then starting new seedlings under grow lights so they’ll be ready to go in shortly after the previous plant has been removed. During the summer I don’t use the entire space, so I can use some of that greenhouse space for potted plants that can’t stay outside when it’s too cold. I use the GrowVeg Garden Planner with its month-to-month feature to rotate the plants on my Greenhouse chart.
WHAT GROWS IN THE GREENHOUSE?
WINTER: After several years, I’ve learned a few things about how things grow and when and where I should plant things in the future. I’d had high expectations that things would grow like they do outside, since the optimum warmth would be kept high. However, without the addition of an artificial light source, the plants receive fewer hours of light per day during the winter months. They grow much more slowly than they do in summer outside! As the spring days gradually getting longer, the plants grow faster. Some things do better than others: the cold-season crops such as kale, chard, spinach and lettuces have done well during the winter. The tomatoes are quite productive, but the tomatoes are smaller and ripen much more slowly than in summer months. Since our greenhouse is not as tall as stand-alone greenhouses typically will be, I can’t plant tall things. I’ve learned to stay with “compact” varieties of all plants, especially tomatoes. The only exception to that is I usually plant one or two indeterminate tomatoes that can be trained along the beam above.
SUMMER: In summer months the greenhouse is used primarily for tomatoes, peppers, cucumbers & occasionally a winter squash or two (smaller, compact varieties). The tomatoes & pepper do not do well outside here and are reserved for greenhouse growing. I try to keep the tomatoes in the bed that’s farthest from the front windows, as it can be quite hot in those front beds, even for tomatoes. Since the winter squash can be started much earlier in the greenhouse than it can outdoors, I’m often able to use the male flowers from the greenhouse to hand-pollinate the outdoor squash. Since natural pollinators are few in the mountains, I depend on hand-pollinating the squash.
When planting the beds by the windows, I had planted some of the larger things, such as kale and swiss chard, at the back of the beds, thinking that the shorter plants in front should be more accessible to me, but I wasn’t thinking about the larger plants by the windows shading the plants closer to the inside edge. Although the shorter plants may be harder to get at, they should have been planted closer to the windows behind the taller plants from the perspective of where I stand to work.
I’d read that growing zucchini vertically is a space saver, and a good way to grow it in a greenhouse. I tried that, and I’m glad I did. Rather than having the plant sprawl across the bed, it is growing nicely upward, saving space around it for other things. The zucchinis are easy to see and easy to pick.
With the year-round greenhouse, I have little need to do canning! I used to plant LOTS of tomatoes and spent the late summer months in the kitchen with dozens of canning projects. Now that I have year-round tomatoes, I rarely do canning, unless I have an over-abundance of tomatoes all at the same time. I’ll occasionally make just a couple of my favorite recipes, such as sweet chile sauce. Additionally, I used to grow extras of things like broccoli or cauliflower for freezing or cabbage for sauerkraut during the summer months, but I no longer do that: I can enjoy it fresh all year. I reserve the outdoor garden for the things that cannot be grown in the greenhouse or just do better outside.
GREENHOUSE PESTS
The greenhouse suffers from two pests: aphids & pill bugs. I do my best to control them but they keep returning.
APHIDS: For aphids I spray with neem. This seems to work the best. The aphids are especially bad on peppers, and make me not want to grow peppers in the greenhouse again.
PILL BUGS: These don’t do too much damage to the larger plants, but they often eat small seedlings until there’s nothing left. They really like the brassicas, spinach and young tomatoes, and pretty much leave the lettuce alone. I’ve begun putting collars of cut bottles or cans around the seedlings until they are big enough to withstand a little damage. In some cases the collars stay around the stem for the life of the plant. Gallon vinegar bottles cut into 2″ collars work well for this.
- Laurie
- Revised September 2022, March 2023