Being a gardener is an open invitation to answer questions. I have done it for a long time, from answering them in magazines, on the Garden Roadshow when we visited flower shows, on the radio, and now I do lots in various forms. Some are easy to understand while others are more challenging when there is not enough information to come to a firm answer. It is also interesting how people see things differently and pick out strange characteristics to help identify plants – such as ‘it has green leaves’.

A recent question I had to deal with was ‘why are my plug plants dying?’. This is a tricky one to answer because so many plants are sold as ‘plug plants’, from clematis to salvias. All these plants need slightly different conditions, and unless I am told what the grower was doing all I can do is guess, but here are some reasons:

These plug plants will have been grown in perfect conditions, before being put in their packs for dispatch. Many will be tender plants and will not tolerate cold. It is surprising how many people think that they can buy plug plants and then grow them on in a garden shed. These plants need warmth and light and, at a push, will be OK on a windowsill in a cool room for a while. But the cold nights we have had recently will do them harm, especially is they are soaking wet too. Of course, these tiny plants must be unpacked as soon as they arrive and checked to see they are not dry.

Overwatering is an issue too. The tiny plugs have little root and they should be put in cell trays or small pots. If potted into big pots those tiny rootballs will be overwhelmed by the mass of wet compost and rot. They need careful watering to encourage root growth. Overwatering is always a bad thing – the roots die and the plant wilts – looking as though it is too dry. If the plant is a little bit dry it can usually recover when watered – if the roots are dead it has little chance.

Over-firming is another issue linked to overwatering. Multipurpose compost does not need firming apart from the settling that occurs with watering. If you crush all the air out of the compost the roots will suffocate, especially if you are too generous with watering, and the plants will decline.

Deep planting. Some plants are very sensitive about how deeply they are planted. The worst are probably dianthus – a common plug plant. Bury their necks and they are very prone to rotting and dying so plant them with the original rootball at the surface or even slightly proud. Lavenders and strawberries are also picky.

Hardy plants do not need to be kept indoors at all and these are best potted and kept outside. But here they are left to the vagaries of the weather (heavy rainfall) and the predations of slugs and snails.

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