How to Choose Plants for Greenhouse
Most gardeners manage to grow almost anything they want with the aid of a cold greenhouse, a heated propagator inside it, and a sheltered garden outside. Nevertheless, they will still need to make a choice as it’s not possible to grow everything under cover where space is often very limited! When choosing what to grow, be imaginative, you could go for foliage plants to give you year-round interest and color, depending on your degree of heat. The weather being kept off allows for some spectacular shows and these will endure much longer than most flowers. In a conservatory, it is probably more important to choose well-formed or well-shaped plants with good foliage. Indoor topiary, trained climbers, and tender wall shrubs all offer great potential and aesthetic interest without cropping or even blooming. Many flowering plants have great perfumes, which are more intense when grown undercover and many, such as the daturas (Brugmansia spp.), gardenias, citrus, and hoya are all good conservatory subjects and would also do well in a warm greenhouse. Cool and cold greenhouses can have excellent shows of “normally” outdoor flowers, and over a much longer season. They are especially good for growing cut flowers to bring into the house. Food crops are usually absent in a true conservatory, but don’t forget that certain herbs and cirrus will do well there in winter. At the other end of the scale are poly tunnels. People always imagine poly tunnels are useful only for utilitarian crop producers, but they can be extravagantly planted with gorgeous flowers for your own, very private show! I use mine for pineapples, bananas, and guavas, and new potatoes in time for Faster. However, it’s your space-so grow what you want.
Forcing plants
One of the problems in winter is that there is insufficient light for plants to actually do much real growing. Plants that store up energy underground can be coaxed into growth by providing warmth, often from underneath. Plants of asparagus, seakale, rhubarb, and Belgian endive all benefit from being brought into the warm (and usually dark) indoors, where they are forced to throw succulent new shoots for our culinary delight.