Capers originate from very dry and nutrient poor areas in the Himalayas and the Mediterranean area. They are the unopened flower buds of a evergreen shrub that can grow up to 1 - 2 meter high. This shrub is self-fertilizing. You can grow this shrub on sandy and clay soil, but it needs good drainage. It needs a lot of sunshine, so don't put this shrub in the shade. It has a good tolerance against drought.
You eat the stil unopened flower buds and young shoots of this shrub. The flowerbuds can be pickled in vinegar or preserved with salt and used as seasoning. You can also use them to give flavour to salads, sauces, pizzas and pasta sauces. Hardiness: -5 °C tot -10 °C. Height: 100 - 200 cm.
Soaking: 2 - 3 days
Indoor sowing: January - April
Germination: 60 - 90 days
Sowing temperature: 18 - 21 °C
Sowing depth: ½ - 1 cm
Plant distance: 90 - 120 cm
Plant position: very sunny
Harvest period: from the 3rd year after sowing. May - September
Because the seeds can germinate very irregularly, it's wise to soak them in tepid water, 2 - 3 days before sowing. Sow the seeds in a tray filled with moist and loose potting soil mixed with vermiculite, perlite or river sand. Or use propagation soil mixed with vermiculite or perlite. Put the trays in a propagator. When no germination has occured within 60 - 90 days, there are 2 possibilities in order to let the seeds germinate.
Option 1: put the seed trays outside in a shady position. Leave the seeds in the winter outside to go trough a natural cold period, and the following year the seeds will probably germinate.
Option 2: put the seed trays 7 till 10 days in the fridge. Put them afterwards back in the propagator.
Put the seedlings, when they're large enough to handle, in seperate pots of about 7½ - 9 cm. Put the pots away at a minimum temperature of 10 °C. You need to keep the plants moist in their growing period from the spring till the autumn. But keep the plants dryer in the winter. Don't overwater because capers hate wet soil. Give them a liquid feed high in potassium every week from the spring till the autumn. Let the young plants overwinter in the greenhouse in their first winter. You need to If it is extremely cold, the plants need to be heated. It should not be colder than -5 °C.
In our climate, it's wise to overwinter your shrubs frost free or to cover them up against the cold. Put the plants in large pots filled with a mixture of potting soil and sand, vermiculite or perlite and put shards of old pots or pebbles at the bottom for good drainage. So you can put your pots indoors in a greenhouse in winter to hibernate frostfree.
You can start to harvest capers from the 3rd year after sowing from May till September. Harvest the closed flower buds and pickle them with vinegar of preserve them with salt. Harvest the flower buds very early in the daytime, because they open under the sun. You can prune, from the 3rd year after sowing to give a better shape to the shrubs.