Garden glossary

Sowing on a windowsill long before it is warm enough outdoors.

Heat-loving crops like tomato, pepper and basil need more summer than the German climate provides. Sowing them indoors in pots from February or March buys six to ten weeks of season. They only move outdoors much later.

The seed goes straight to its final position in the bed.

No detour via a pot. Carrots, radishes, beans, dill and spinach want it this way — they form a sensitive taproot and resent being moved. The trade-off is waiting until the soil is warm enough.

Something ready goes into the bed: a young plant, clove, set or tuber.

Usually a pre-grown young plant moves from its pot into the bed — the most delicate moment of the gardening year, and for frost-tender crops not before the Eisheiligen. But some crops are never sown at all: garlic goes in as separate cloves, onions and shallots as sets, potatoes and Jerusalem artichokes as tubers, tarragon as a root division. For those there is no sowing date, only this one.

The window in which there is something to pick.

For most crops a span of weeks or months, not a single date. Some are picked leaf by leaf as needed (loose-leaf lettuce, chard, kale), others come out all at once (butterhead lettuce, pumpkin, onions).

Moving seedlings from the seed tray into their own pots.

Once the first pair of true leaves appears after the two seed leaves, move them on. Each plant gets root room, and you get sturdy compact seedlings instead of long thin ones.

Thinning out seedlings that came up too densely.

Direct sowings almost always come up too thick. Remove the surplus so the ones that stay get their full spacing. It feels wasteful, but it is the difference between finger-thick and pencil-thin carrots.

Acclimatising young plants before they go outdoors.

For about a week before planting out, put the pots outside during the day and bring them in at night. Without this introduction to wind, sun and temperature swings the plants get a shock and sulk for weeks.

Seed that germinates only in light — do not cover it.

Lettuce, celeriac, basil, thyme and oregano are pressed onto the surface, not buried. This app shows them as 0 cm sowing depth. Dark germinators like pumpkin or beans want the opposite: reliable cover.

How deep the seed goes under the soil.

Rule of thumb: about twice as deep as the seed is thick. Sown too deep it never emerges, because the seedling runs out of energy before it reaches light. 0 cm means a light germinator.

Distance within a row and between rows.

Planted too tightly you get small fruit and encourage fungal problems, because the foliage never dries after rain. Row spacing is also simply the room you need to hoe and harvest.

11–15 May — the frost line of the German gardening year.

An old farming rule that holds up surprisingly well: only after these days is the late-frost risk considered largely past. Every outdoor date for frost-tender crops hangs off it, and this app’s climate bands shift exactly that line by ±14 days.

The three bands this app uses to shift your dates.

There are about four weeks of growing season between the Upper Rhine valley and the Erzgebirge. "Mild" runs two weeks ahead of average, "harsh" two weeks behind. Your federal state only supplies a suggestion — uplands run later than the lowland next door, which is why you can always override the band.

How much cold a crop tolerates.

Hardy means it stays in the bed all winter and frost often makes it sweeter (kale, parsnip, lamb’s lettuce, sprouts). Half-hardy takes a light frost. Frost-tender means one night below zero and the plant is finished.

The plant switches to flowering and turns inedible.

Instead of making more leaves the plant throws up a flower stalk. Lettuce, spinach, rocket and coriander turn bitter and tough when it happens. Heat and long days trigger it — which is exactly why those crops have a spring and an autumn window in this app, with a gap in high summer.

Whether the plant disappears after one season or returns.

Annuals are re-sown every year. Perennials like chives, thyme, sage, mint or lovage come back on their own each spring — they need a permanent spot that does not get dug over annually.

Drawing soil up around the base of the plant.

Mainly for potatoes: once the foliage is about 20 cm tall, pull soil up around it. Tubers that reach daylight turn green and are then no longer edible. It also adds stability and root space.

Covering the soil with clippings, straw or leaves.

A layer of organic material on the bed keeps moisture in the soil, slows weeds and shields soil life from harsh sun. Keep it off young stems, which otherwise rot underneath it.

Growing crops side by side that help each other.

The classic is carrot next to onion: the smell of each distracts the other’s pest. Summer savory among beans, or basil among tomatoes, are equally common pairings.

Do not put the same plant family in the same bed two years running.

Otherwise soil-borne pathogens build up. For brassicas that is clubroot, which persists in the ground for years — and swede counts botanically as one, however root-like it looks. Rule of thumb: a three or four year gap.

How much a crop draws out of the soil.

Heavy feeders like cabbage, tomato, pumpkin and potato want well-fed soil. Light feeders like herbs, lamb’s lettuce and beans manage on little. The usual sequence in a bed is heavy, then moderate, then light.

A thin white sheet laid over the bed.

Lets light, air and water through while holding off a few degrees of frost and excluding vegetable flies. It extends the season by two or three weeks at each end — and on carrots and brassicas it saves you the worst of the trouble.