What to sow and plant in the vegetable garden in May?

By region

Tomato planting in May–June in the north, and April–May in the centre, is from Valle d'Aosta and Umbria's calendar; the 16 °C is from the RHS. Onions, a March seedbed and a May transplant or direct sowing, are from the Valle d'Aosta Informatore. French beans, with the 10–12 °C and the close at the end of July, are from ARPA Umbria's sheet; the 16 °C and the 32 °C are from Cornell. Potatoes on the valley floor, with tubers forming in May and June, are from the potato issue of the Informatore; 30 June is from Colfiorito; early May for the main crop is from Campania. Broad beans through early May are from the RHS. Basil, with 10 °C nights and 20 °C for sowing, is from the RHS, and the 18 °C soil figure is from University of Minnesota Extension. Spring strawberries are from the RHS. If the packet gives another window, the packet wins. April is in the April calendar, June in the June calendar, and the wider picture in the planting calendar.

Tomatoes and onions

In the north, tomatoes go into the open ground from May to June, only once temperatures stay above 16 °C. In the centre the written window closes in May. In the south you have been planting since April, at the same threshold. A couple of weeks of hardening off come first. If nights still freeze, the plant stays under cover. Peppers and aubergines go out with the same caution: these calendars do not give them a separate field month. The months are in when to plant tomatoes.

Onions sown in March are transplanted now, in Valle d'Aosta. Direct sowing, then thinning, is a May job and only in the lower valley. Higher up, the text prefers sets planted in autumn, because they finish the crop sooner. In the south, spring is one of the written windows, and Cipollotto nocerino is already being harvested. The windows are in when to plant onions.

French beans, broad beans and potatoes

Sow French beans once frost has passed and the soil is warm. Below about 16 °C, germination is poor. In Umbria the window, opened in April, runs to the end of July. In the south, towards 32 °C, pod set is poor: sow before the hottest part of summer, not into it. One seed to a pot, as the RHS says if you start early, and move the whole root ball. Depth and spacing are in when to plant French beans.

Broad beans only in early May. Then the RHS closes outdoor sowing; the other window is autumn, in mild areas, with hardy varieties. See peas and broad beans. Peas in Campania closed in March. Elsewhere, in May, what counts is whether the soil is past 10 °C, and the packet.

On the valley floor, potatoes in May are forming tubers, if you planted by 20 April. Cover the shoots if it freezes. In Umbria you can still plant, through to 30 June. In Campania the main crop runs to early May, then you wait until late July for the second crop, on the coast. The detail is in when to plant potatoes.

Basil and strawberries

Basil goes outside only once frost has passed, nights stay above 10 °C and the soil is about 18 °C. The month on its own is not enough. Indoors, sowing continues, from March to July, at about 20 °C. The page is when to plant basil.

Strawberries can still be planted, if the soil can be worked. Cold-stored runners arrive through to early summer and, in good conditions, fruit about 60 days later. Cover the flowers at night if frost is forecast. Crown and spacing are in when to plant strawberries.

Jobs for the month

Water the soil, in the morning, not the leaves, and keep it even on tomatoes just planted out: swings split the fruit. How much is in watering. A mulch on soil that is already warm holds water: materials and depth are in mulching. A pot needs it more often, as in the container garden. If a late frost is forecast, fleece at night and off again by day. Anyone still sowing indoors follows starting seeds indoors.