How to grow tomatoes

Frost-tender · Nightshade family

When to sow and plant

Start indoors 11–25 March
Plant out 6–20 May

Frost-tender: everything 17 days later, so it only goes outside once there is no frost in 9 out of 10 years.

Based on: average for Germany, last frost 19 April, safe from 6 May

Where the dates come from

The weeks come from our sources; the dates use the average frost in Germany. Enter a German postcode to get dates for your area.

Start indoors: 6–8 weeks before the last frost (UNH Extension: How do I know when to start seedlings indoors?)
Plant out: 0–2 weeks after the last frost (University of Maryland Extension: Growing Tomatoes in a Home Garden)

Good and bad neighbours

Good neighbours · 5

BasilStudy· B
In garden trials, tomato and basil together out-yielded either crop alone – especially when planted densely.
B: Hint from one study
Basil
French marigold (tagetes)Study· B
In a greenhouse trial, whiteflies built up more slowly on tomatoes next to French marigolds (limonene). Other mixed partners had a similar effect.
B: Hint from one study
French marigold (tagetes)
White cabbageStudy· B
In two field trials in Myanmar, cabbage next to tomatoes had markedly fewer diamondback moth caterpillars. Cooler climates were not tested.
B: Hint from one study
White cabbage
CarrotExpert rule· C
Carrots dislike heat; tomatoes give them shade.
C: Expert rule with a reason
Carrot
Butterhead lettuce, Loose-leaf lettuce, Iceberg lettuceExpert rule· C
Lettuce bolts in heat; in the shade of tall tomatoes it stays tender longer.
C: Expert rule with a reason
Butterhead lettuce Loose-leaf lettuce Iceberg lettuce

Better not next to it · 1

PotatoExpert rule· C
Both get late blight; side by side, tomatoes catch it more easily.
C: Expert rule with a reason
Potato

Gardeners’ lore, not proven · 3

ParsleyLore: good· D
Traditional advice, not tested.
D: Tradition, named by at least two sources
Parsley
RadishLore: good· D
Traditional advice, not tested.
D: Tradition, named by at least two sources
Radish
Florence fennelLore: bad· D
Traditionally seen as bad neighbours; no proven reason.
D: Tradition, named by at least two sources
Florence fennel

Crop rotation

After the nightshade family, leave the bed free of it for at least 4 years.

The same species should go back to the same spot after a break of 3 years at the earliest.
Example: grown here in 2026, again from 2031.
Heavy feeders two years in a row on the same bed are not a mistake, but they take more out of the soil.

At a glance

Family: Nightshade family (Solanaceae)
Nutrient needs: Heavy feeder
Frost: Tender to frost
Spacing (row × plant): 80 × 50 cm (31 × 20 in)
Plants per m²: 2.5
Per square foot (30 × 30 cm): 1 plant per 4 squares
Life cycle: Annual
Harvest: After 65–90 days from planting

Spacing according to Bayerische Gartenakademie (LWG): Sä- und Pflanztermine auf einen Blick (2018). Other sources: 61–91 × 61 cm (24–36 × 24 in) (USU Extension: How to Grow Tomatoes in Your Garden); – × 45–60 cm (– × 18–24 in) (RHS: How to grow tomatoes).

Questions and answers

When can I plant out tomatoes?

Plant out, average for Germany: 6–20 May. That is the date after which there is no frost in 9 out of 10 years. Enter a German postcode above for your area, or your own frost date in the planting calendar.

How far apart should I plant tomatoes?

80 × 50 cm (31 × 20 in) (row × plant), according to Bayerische Gartenakademie (LWG): Sä- und Pflanztermine auf einen Blick (2018).

What grows well next to tomatoes?

Basil: Good neighbour (B), French marigold (tagetes): Good neighbour (B), White cabbage: Good neighbour (B), Carrot: Good neighbour (C) and Butterhead lettuce, Loose-leaf lettuce, Iceberg lettuce: Good neighbour (C).

How long a break do tomatoes need in the same bed?

After the nightshade family, leave the bed free of it for at least 4 years. The same species should go back to the same spot after a break of 3 years at the earliest.

Sources

Show 19 sources

Retrieved on 23 October 2026. Facts in our own words, one source per value.