Welcome to the brave new world of greenhouse gardening! A garden without a greenhouse is like a house without a refrigerator or washing machine. Once you start using yours, you will wonder how you ever gardened without one. Suddenly your gardening will step up a level. The propagation bug is seriously compelling. Nothing is quite like a healthy tray of healthy seedlings to get a green-fingered pulse racing.
So, how to get started? Firstly, the golden rule is to keep it simple. Your greenhouse will be used for three main purposes: raising seedlings and young plants, overwintering tender plants, and growing tender annual crops like chillies, cucumbers and tomatoes. These different functions require different cultivation techniques, but all of them have a few basics in common.
Firstly, ventilation is incredibly important to get right. A close, stuffy atmosphere breeds pests and diseases, much like a stiflingly overheated house breeds illness in wintertime. Use the vents not only when temperatures outside are balmy, but on sunny winter days when, especially if your greenhouse is sited, as it ideally should be, in a south-facing location. You will, of course, be spending lots of time in your new retreat, so you will soon learn to gauge when the vents need opening or closing.
Water is the other common factor in all methods of greenhouse cultivation. The only foolproof method of keeping water at its optimum level for each plant is to be present. Don’t spread yourself so thinly that you cannot remain on fairly intimate terms with each plant or group of identical plants in your greenhouse. This may sound rather eccentric, but being on familiar terms with each plant means you can check it frequently for dryness. No two plants have the same water requirements, so a blanket watering regimen is likely to fail. Watering cans are more effective than hoses, because you can give each plant close individual attention.
Space between plants is just as vital as ventilation when it comes to greenhouse cultivation. If plants are crammed in, diseases spread and growth is stunted. Again, opt for a small number of treasured, well-tended plants rather than an unmanageable quantity of neglected ones. It is tempting to get carried away and bite off way more than you can chew when you see all those enticing seed packets on the shelf, but be realistic. How many courgette plants can you really fit into your vegetable patch? If your enthusiasm has got the better of you, give away extra plants to friends and green-fingered neighbours. They will thank you come harvest time, and maybe even give you some of their garden bounty in return.
Pay attention to the soil you use in pots and greenhouse beds. Again, there is no hard and fast rule, because different plants love different soils. There is no one size fits all, and just as we all enjoy different foods, so do our plants. Use organic composts where possible, and if you have your own compost heap and take the time to develop your own potting compost, you will save a lot of money over the years, particularly if propagation becomes a serious pastime.
You can easily make liquid teas from wild and garden plants, like nettles and comfrey. Some teas promote leaf growth, whilst others promote fruiting. Using and applying these sparingly during cultivation can help ensure a good crop of produce, positively glowing with health. Tomatoes benefit hugely from dilute feeds, and so if you plan to make your own, make sure you brush up on recipes and application schedules before the growing season starts around late March.
If you follow the basics discussed above, you will have healthy plants which are reasonably pest resistant. However, vigilance is the best prevention, and again, if you opt for quality over quantity, it should be possible to monitor your greenhouse occupants and quickly eliminate infestations.