How do I feed my greenhouse plants?

For complete control over your plants development choose to use a liquid fertiliser. These are usually diluted and applied to the plants weekly, or fortnightly. Simply follow the instructions on the bottle.

Seedlings and cuttings should be fed sparingly, if at all. If you have chosen to grow them in dedicated seed and cuttings compost then this contains the correct low level of nutrients that the plants require at this stage of growth. The fresh new roots are very delicate and can be scorched and damaged by standard plant feeds. It is better to replant the young plants into a potting compost, John Innes No 1 or a young plant compost, this has the next level of nutrients needed to sustain healthy, uniform plant growth. By the time your plant has reached its third potting stage it should be mature enough to plant into a multipurpose compost, which should contain enough nutrients to support it through the next four to six weeks of growth.

Use your plants as indicators. They will tell you when they need feeding, by starting to lose their rich greenness and turning more yellow. Really starved plants will become yellow or chlorotic. Don’t let them get to that stage, feed at the first sign of deficiency and use a quality plant food.

For developing plants and cuttings that are old enough to be fed choose a balanced liquid feed for all plant types. Then as your plants start to mature, feed with a more tailored feed. Flowering and fruiting plants need a feed formulated to enhance flower production. Choose one that is high in potash (K) to encourage strong flowers.

Tomato plants are flowering plants, but actually demand a few other trace elements that many flowering plants don’t need. Use a dedicated tomato feed to feed tomato plants, this will contain all the major and micronutrients that your plants need. A tomato feed can also be used to feed other fruiting plants such as peppers, aubergines and cucumbers.

Plants that are grown more for foliage such as salads, spinach, brassicas and many houseplants need a feed rich in nitrogen to boost leaf production. Don’t ever be tempted to increase the dose, too much sappy growth is a magnet for pests and much more susceptible to temperature fluctuations.

Make sure your plants are well watered but not over wet. Never apply plant food to dry roots as you risk damaging them, instead water your plants first and allow the roots to rehydrate for a few hours or overnight if possible and then feed the following day.

Permanent greenhouse crops such as fruit in containers and planters can be fed using a slow or controlled release fertiliser that is added to the compost as granules or tablets. These feed the plants for several months at a time and are a great time saver for gardeners that are stretched for time. You can also apply a diluted liquid feed if necessary if plants need an extra boost.

To know more about growing plants in your greenhouses visit http://www.growhouse-greenhouses.co.uk/greenhouses.php