Growing rocket in a trough
Rocket grows so fast it feels almost unfair: four weeks after sowing you cut the first leaves. Along with radish, it is the quickest route from seed to plate. The only real skill is timing, because heat turns rocket harsh and woody within a week.
At a glance
- Light
- 3 to 5 hours, prefers cool conditions
- Pot depth
- Trough 15 cm deep
- Sowing
- March to May and August to September
- Harvest
- 4 to 6 weeks after sowing
- Water
- Regularly — drought sharpens the flavour
- Level
- Very easy
Sowing
Sow thinly, half a centimetre deep, about two centimetres apart. Rocket takes closer spacing than most crops because you harvest it young, but too dense gives long floppy stalks.
Resow every two or three weeks. One trough gives two to three harvests before flowering; a fresh sowing keeps the supply going.
Heat is the enemy
Rocket is a cool-season crop. Above twenty degrees it bolts fast, and the leaves sharpen considerably at the same time — that mustardy bite that catches people out.
Put the trough in partial shade in July and August, or skip those months and sow again in late August. The autumn crop is almost always milder than midsummer's.
Harvesting
Cut the outer leaves at about ten centimetres and leave the heart. Young leaves are milder; let them grow larger and the heat builds.
If the plant flowers you need not bin it: the small white flowers are edible and taste like mild rocket.
Common mistakes
Sowing in June and being surprised by the sharpness. That is not a growing mistake but a calendar one: sow in spring or autumn.
Small holes in the leaves come from flea beetles, which like dry warm conditions. Fine insect mesh over the trough solves it completely.
Frequently asked questions
Why does my rocket taste so sharp?
Heat, drought or leaves left too long — usually a combination. Harvest younger, water evenly, and keep the trough out of full afternoon sun in summer. Spring and autumn crops are noticeably milder.
How often can I harvest from the same trough?
Two to three times before the plant bolts. Sow a new trough every two or three weeks for a continuous supply.
Can rocket grow on an indoor windowsill?
Yes, and it is one of the better choices for an east- or west-facing window. Indoors also stays cooler in summer, which keeps the flavour mild.
Updated on 2026-08-25
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