HARVESTS of early potatoes, onions and garlic in June and July can suddenly produce a welcome crop of empty space on the midsummer allotment. Here are three vegetables you can sow now, to fill the gaps through to autumn.

Bulb fennel, also called Florence fennel, should never be sown before July, despite what you might read on the seed packet. If started before the longest day of the year, it has a strong tendency to bolt, so that you end up with a thin, tough stem instead of a fat, juicy bulb.

It needs good soil, moisture-retentive and fertile, in a sunny spot. Heavy or stony ground, wind, or any period of drought will interfere with the swelling of the leaf bases — the edible part which is colloquially referred to as the “bulb.”