What fruit to plant

Below are compact guides as to what fruit you could grow in your windowbox and how to grow it, with recommended cultivars that are known for their ease of growing, good flavour, size or hardiness. For obvious reasons I've not included any fruit trees here, but certain fruit bushes and shrubs may be possible depending on the size of your windowsill.

Berries (A-G)

Berries (H-Z)

Herbs, etc..

Currants

Vegetables

Pernettya (syn. Gaultheria)

More often grown as a winter ornamental plant, Pernettya or Winter Heath, produces attractive red, pink or white fruits that have a slight crunchy, appley taste.
Prefers an acidic, moist soil to do well. Trim to size as needed.
Plant: Pot grown plants at any time of year.

Physalis (Cape Gooseberry)

A small, tender shrub, related to the tomato, with fruits held within a papery pod. Enjoys full sun in fertile soil. Use fruits as a garnish or dipped in chocolate.
Sow: Seed in pots, indoors from early to late spring. Transplant out in early summer.

Raspberry

Unfortunately due to the height they grow to, raspberries are not suitable for a windowbox.

Strawberry

Easily planted as pot-grown, bought in plants or ‘runners’ (ie. The baby plants which appear as spurs off other adult plants), strawberries like a fertile, free-draining soil, preferably in good sun . White or pink flowered varieties are available. Water well to establish, but avoid watering overhead when fruit has set.
Sow seed: Early to mid spring, thinly in pots, then transplant
or Plant: Runners in late summer, potted plants in early spring
Varieties: Hapil, Cambridge Favourite, Aromel

Strawberry (Alpine)

Best grown from seed then planted out in a fertile, well-drained soil in sun or semi-shade. Easily self-seeds.
Sow seed: Early to mid spring thinly in pots, then transplant.