Kohlrabi

Growing in Pots, Balconies & Indoors

kohlrabi can be grown in a large, deep pot on a patio or balcony, though it needs room and a long cool season to form a solid head. The grower does not list it as an indoor houseplant; a sunny windowsill is really only useful for raising seedlings or picking baby leaves, since a full head will not firm up in a room.

Quick Details

• Container Size: A large, deep pot around 25-30 cm (10-12 in), one plant per pot
• Indoor Suitability: Not a houseplant; a bright sill suits seedlings and baby leaves, but plants must head up outdoors
• Best Spot: full sun, with light shade in heat – a sunny, open balcony or patio
• Soil & Drainage: Rich, firm, well-aerated organic mix; free-draining but moisture-retentive
• Watering in Pots: Keep evenly moist – pots dry fast and uneven watering splits heads; never waterlogged

Indoors & On the Windowsill

• Houseplant limits: Not a houseplant – a heading crop needs full outdoor light and cool air to firm up; indoors it stays loose and pale.
• Windowsill use: A bright sill is fine for starting seedlings or cutting baby leaves and microgreens, but move plants outside to develop properly.
• Overwintering: Hardy types tolerate cold outdoors; over a hard winter, shelter pots in a bright, unheated spot rather than a warm room.

On a Balcony or Patio

• Light & wind: Full sun, with some relief from the fiercest afternoon heat. A big pot will not blow over, but keep exposed balconies sheltered. Reflected heat from walls and paving dries pots fast.
• Practicalities: This is a hungry crop that wants a good volume of mix – one plant per large pot – and you should mind the drainage runoff.

Choosing the Pot, Soil & Long-Term Care

• Pot & drainage: A large, deep container (roughly 25-30 cm / 10-12 in across and deep, one plant each) with strong drainage holes; no standing-water saucer. Terracotta breathes and dries faster, glazed or plastic holds moisture longer.
• Potting mix: A rich, fertile, well-aerated organic mix; brassicas like a slightly firmed medium.
• Feeding: A hungry crop in a pot – feed regularly with a balanced, nitrogen-leaning liquid feed as nutrients leach out.
• Between crops: Refresh or replace the mix each season; these are annual or biennial croppers rather than long-term pot residents.

Bloom & Edible Flower Guide

Quick Details

• Bloom Season: Summer
• Time to First Bloom: Usually in the second year — kohlrabi is grown as an annual but is biennial to flower, bolting after winter cold; it may run up early if young plants are chilled or stressed
• Flower Appearance: Small four-petalled yellow flowers on upright clusters (racemes)
• Edibility: Edible — the buds and flowers can be eaten raw or cooked, with a mild, sweet cabbage flavor

Detailed Blooming Overview

Kohlrabi is grown for its swollen, above-ground stem, which is harvested while young and tender. Left in the ground and exposed to cold, the plant bolts the following season, sending up a branching spike of small yellow cruciform flowers.

Flower Characteristics

• Small four-petalled (cruciform) yellow flowers on upright racemes.
• Followed by slender seed pods (siliques) if left to set.

Bloom Care & Thinning

• Managing the bloom: Harvest the swollen stem before the plant bolts, as it turns woody once flowering begins. Leave the flowering stalk only for seed or for pollinators.
• Pollination: Pollinated by bees and butterflies; largely self-incompatible, so cross-pollination improves seed set.

Bloom Health & Protection

• Cabbage aphids: Grey-green aphids often cluster on flowering shoots and buds; a strong jet of water, insecticidal soap or neem oil keeps them in check.
• Cabbage white caterpillars: These can graze buds and open flowers — a Bacillus thuringiensis (Bt) spray is a targeted, low-impact option.