Crop shelter for early and late harvests
When we were commercially doing greenhouse vegetable gardening, I learned a few things I’d like to pass along here. This isn’t your normal pie-in-the-sky kind of advice but hard-earned advice from our own growing days. You can indeed have vegetables year round in your greenhouse *if* you’re prepared to do the work and pay the price. Or, select a few vegetables that are very cold tolerant and set up your greenhouse to grow only those. So let’s take it from the top.
The first thing
The first thing to understand is that it is possible to have a year round supply of vegetables from your own greenhouse.
The Second Thing
You have to pay attention to the plant needs. 🙂
This means can’t get high light crops such as tomatoes year round unless you’re prepared to put a lot of energy into lighting and heat. Frankly – it’s far cheaper to buy good organic produce in the northern winter than it is to throw energy and lighting-costs to keep tomatoes in production.
But you can get low-light and cold-tolerant vegetables such as spinach, kale and cabbages from a low-energy greenhouse.
It’s all about setting your expectations in tune with Mother Nature and the winter light and temperature she tosses at you.
The Third Thing
Vegetables in a greenhouse require the same kinds of conditions inside as they do outside. So if a tomato requires 60-65F to set pollen (it does) and stops producing pollen and viable fruit at lower temperatures, then the climate is set by the plant and you have to provide that temperature if you want fruit.
If vegetables stop growing around 83F because high heat shuts down the photosynthesis in the leaves (they do) then you have to heat and ventilate during the growing season to keep the temperature within the 60-83F growing range.
The Fourth Thing
We usually consider growing in home scale greenhouses not to overwinter tender plants but to extend our harvest of plants. So we can start hardy plants such as spinach very early in the spring and the odd frost or two that gets into the greenhouse isn’t going to be a problem.
We can grow our tender melons and tomatoes in a summer greenhouse (with good ventilation or shading) so the season extends into the fall and we can harvest fruit until the plants die in the cold temperatures or stop yielding.
So when it comes to greenhouse vegetable gardening, think season extending and hardy plant growing
The Last Thing
I said above that vegetables in a greenhouse require the same conditions inside as outdoors. And this is true – but in a greenhouse, you can precisely control those conditions to create great crops.
For example, I used to grow tomatoes and greenhouse cucumbers in green plastic bags. The bags were very cheap , would hold as much soil as I needed for the crop (usually 6-8 shovels of soil) and were easy to clean up in the fall. I’d toss them into a trailer and dump the used artificial, peat-based soil onto our compost piles along with all the old leaves and stems.
But with this amount of soil, I had to water twice a day on hot days because a mature tomato plant sucks a lot of water. And if I missed watering, I could count on the fruit developing blossom end rot.
So while you can control conditions precisely for each crop, it is also necessary to do it if you want a harvest.
But it isn’t rocket science. You can do it. It might take a bit of study and practice but greenhouse vegetable gardening is quite possible.