Q. I’ve heard that banana skins are good for roses. Are they good for other plants too? Mike

A. Banana skins are rich in phosphorus and potassium, which are both essential nutrients for healthy plant growth. Phosphorus aids seed germination and root development, while potassium promotes flower and fruit production. Young plants, in particular, benefit from phosphorus while their roots are developing, and root vegetables, such as carrots and turnips, guzzle phosphorus like it’s going out of fashion. Potassium is especially good for crops or trees that bear fruit, and is used in the process of building starches and sugars in fruit and veggies. Tomatoes, peppers, apples, pears, carrots and parsnips, etc, all love it. Cut your banana skins into small pieces and mix them with fresh soil or compost when planting a new flower, vegetable or shrub. Or lightly dig it into the soil around existing plants. Jane

Q. I’d like to transplant my lime tree to another location in the garden. When is the best time to do this? Bronwyn

A. The best time to transplant trees and shrubs is during winter when the plants are dormant, as this ensures minimal shock from root disturbance. For greatest success, a month before you actually shift your tree, dig a circle around the drip line to severe the surface roots. On the day of moving, dig a large planting hole that will accommodate the root ball. Then dig up your tree, keeping as much soil as possible intact around the roots to avoid further root disturbance. Plant the tree in its new home, watering deeply and regularly after planting. Do not fertilise the tree until after a burst of growth in spring, then use a special citrus fertiliser. Jane

Q. Each year my cucumbers, courgettes, dahlias, gerberas, calendulas and other plants get powdery mildew. Is there a way to control this organically? Kelly

A. You can keep on top of powdery mildews with a homemade milk spray. The natural antibiotics in milk, as well as the production of other constituents upon exposure to sunlight, act as a natural fungicide. A dilution rate of one part milk to nine parts water is generally recommended; too much milk can encourage the growth of sooty mould. The spray should be used regularly, every 7 to 10 days, and a good coverage of the leaves is required. Bear in mind that this spray won’t get rid of your existing mildew, but it helps to keep it from spreading.
The baking soda method offers another organic solution. Mix 1 tablespoon of baking soda with a litre of water and spray it over the leaves. Jane

Q. I can collect loads of stable manure (a mixture of sawdust and horse manure). Is this ok for the garden? Di

A. It is, but all animal manures need to be aged for at least six months before adding them to your garden. That’s because ‘raw’ manure releases nitrogen compounds and ammonia, which can burn plant roots and interfere with seed germination. You can dig raw manure straight into your soil, but you must leave the area for several months before planting up. Otherwise, add raw manure to your compost heap, or place it in a disused corner of the garden and let it age. Horse manure often contains weed seeds, so you may like to consider hot composting (where the pile reaches 45-65 degrees Celsius), to kill the seeds. For a hot compost heap, you need to build it all at once, instead of over several weeks. Jane