These last few days have been sunny and warm. I understand the clocks go forward on Sunday. I, for one, have been on the allotment for the past few days. But that doesn’t mean we should be sowing every seed in the back of the garden shed.

Even if we don’t get actual frost yet, the nights are still very chilly for your average two-inch seedling. Some can take it. Broad beans are the Bash Street Kids of the plant world – they can survive all manner of tough conditions. Runner beans – same family, same-looking seedlings – are from South America and one cold night will kill them.

So here are a three types of seeds to leave in the packet… There’s plenty to do in the garden this time of year, mainly tidying up, mowing (unless, like me, you have snowdrops in your lawn*, in which case you need to leave the grass in a disgracefully shaggy state until the leaves have died down if you want another flush next year) and sowing ‘safe’ seeds, such as brassicas (cabbage, Brussels, purple sprouting broccoli etc) radishes (bombproof) and peas (yes, I do put an experimental batch in this time of year. It does sometimes die but if it doesn’t you get a lovely, early harvest).

Runner and fancy French beans, already mentioned. You CAN start these indoors, but don’t be too excited – they have a tendency to get leggy and wrap round each other. These are sprinters of the vegetable world – you can start them quite late and they still make it in time. In fact I often just wait ’til late April and put the seeds straight in the ground; they seem to catch up with the mollycoddled indoor seedlings very quickly.

Sweetcorn – Don’t even think about it. Again, these chaps need warmth, and they don’t like having their roots disturbed. The ideal is to grow them in little individual pots just enough for the roots to almost get too big, and then move them. I’d say leave off at least another month.

Pumpkins and squash – This is another May sow. The leaves might become complete thugs when they’re older but young and tender they suffer a double threat: cold and slugs, which can render the plants invisible in a couple of hours. Leave em’ for the moment. Likewise, I always leave courgettes for a month or so yet. They are tougher than pumpkins but the slugs are still hungry.

The three above are sometimes called the Three Sisters as, in South America they’re grown in the same plot of land. Sweetcorn grows tall, acting as a support for climbing beans. Pumpkins spread across the ground, shading the roots.

By the way, I have tried this and, in the UK it doesn’t seem to work. I think we just don’t get hot enough for the plants to share the soil. I found the beans grew much too fast and left the sweetcorn behind, and the squash just stamped on everything. I’d recommend keeping them in separate beds.

I notice that this weekend is going to get cold. So if you have any teeny seedlings, make sure they’re tucked up indoors…

*By ‘lawn’ I mean a scrubby patch of dandelions, daisies, couch grass, moss and wild garlic, which I mow every couple of weeks in the summer. It’s all green and once mown does me fine…