Greenhousing Adds Precious Days to Season
By Jos Van Hage
Saturday, August 19, 2006 03:43 AM
Our Prince George summers tend to be short when you count how many consecutive frost-free days we get. This is probably why many local gardeners have little backyard greenhouses to extend the growing season. Vegetables such as tomatoes, cucumbers and peppers all grow very well in a greenhouse.
Greenhouse growing has its advantages by a longer growing season with controlled growing conditions but it also has its disadvantages by someone having to water the greenhouse daily and making sure that there is good air ventilation by opening the door and vents. The most problems come from poor air ventilation, fluctuating temperatures and uneven watering.
I think that over 90% of greenhouses have at least one tomato plant in it. Tomatoes grow well but you have to make sure that they are watered on a daily basis. Tomatoes should be kept moist and not be allowed to go dry. By allowing the plant to go dry you will have fewer tomatoes as an end result, and it could lead to blossom end rot which is a black spot found on the bottom of the tomato. Blossom end rot can also be caused by a calcium deficiency which can be remedied.
If possible, always water plants in the morning with room temperature water, and always water the plant at the soil level so that the foliage remains dry. For high crop yields you should fertilize plants with a tomato fertilizer one or two times per week. A common complaint among greenhouse tomato growers is blight, which is a blotch on the foliage and on the fruit which leads to rot if left untended. Blight is caused by poor air circulation when the temperatures become cool or if the humidity is high in the greenhouse, or if the leaves get moisture on them. If you get blight on your plant and it is just one or two leaves you should remove the infected part immediately, and if it is worse than that you should treat the plants with tomato/vegetable dust.
Peppers grow well in the greenhouse and require the same care as tomatoes. To encourage high crop yields you should pick the peppers as they reach full size during the beginning of the season and later in the season the peppers can be left on the plant where they will ripen and change color while still on the vine. I have found in my own greenhouse that pepper plants are the first things that get aphids so I grow my peppers in big 5 gallon pots that I start in the greenhouse and move outside during the summer and then bring them back inside in late August. This seems to stop the aphid problem. If you leave the plants in the greenhouse you should spray the plants on a weekly basis with insecticidal soap as a precautionary measure.
English cucumbers are another crop that grows very well in the greenhouse. The Corona and Carmen varieties seem to do the best. When growing English cucumbers you need to be careful in how you water the plants. If you keep them too wet they become waterlogged, collapse and die and of course you do not want the plant to dry out either so you need to find that happy medium. Cucumbers are heavy feeders so they need to be fertilized once or twice a week with a vegetable/tomato fertilizer. Just like with the peppers you should continually pick the cucumbers when they reach a certain size so that the plant will produce new ones. Cucumbers are quite touchy for mold which is a grey dust on the leaf which spreads quickly and is caused by high humidity. It is important to keep good ventilation in the greenhouse and remove any infected leaves or cucumbers as soon as the mold appears on them. When growing English cucumbers in the greenhouse you cannot grow any other kind of cucumber in the greenhouse or this will cause cross-pollination which will produce odd shaped, or bitter tasting cucumbers.
These are the three most common things grown in the greenhouse but you can grow different types of squashes, beans, eggplants and any other type of heat loving plants in the greenhouse.
-Jos
Jos Van Hage owns and operates three Art Knapp garden centres:
Highway 97 north
Highway 97 south at the Old Cariboo Highway
Highway 16 west
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By the way, I stopped in at the store at the south end of town on my way out over the weekend. Honestly, what a disaster. There is so much horsetail in your tree "nursery," I would be amazed if anyone actually bought anything. Why would they? The root balls of half the trees are damaged, only partially dug in (or out, maybe a customer changed their mind), and the trees themselves... GARBAGE. I can't believe you try to peddle that crap to people, and for that kind of money!