Beetroot

Light and exposure

Beetroot wants full sun. Give it a well-open bed, without shade cast by a hedge or a row of taller vegetables. Six hours of sun a day at minimum give it round, well-coloured roots; in shade, the foliage develops but the root stays small.

It is an open-field vegetable, not a plant for cover. A hot, dry exposure poses no problem as long as watering keeps up, but a shaded, cool bed gives disappointing beetroot. So choose the brightest spot in the kitchen garden.

Watering

Regular watering is the key to a tender beetroot. The soil must stay fresh at all times, without swings. This is where it all plays out: a beetroot that goes thirsty then drinks all at once after rain turns hard, splits, develops pale fibrous rings, and often bolts to seed. Regularity matters more than quantity.

In a dry spell at the height of the growing season, count on a good watering every two or three days if rain is lacking, at the base and not on the foliage. A light mulch between the rows keeps the soil fresh and saves you half the watering cans in hot weather.

Soil and repotting

Beetroot likes a loose soil, worked deeply, fresh and free of stones. Dig or decompact before sowing so the root goes straight down without hitting anything. Avoid fresh manure in the sowing year: it makes the roots fork. A soil enriched the previous season, or a bed of well-matured compost, suits perfectly.

You sow directly in place, never in pots, because beetroot tolerates transplanting poorly. Trace furrows two centimetres deep, spaced thirty centimetres apart, drop a cluster every five centimetres and cover. Emergence takes one to three weeks depending on the warmth of the soil.

Temperature and humidity

The critical point is the soil temperature at sowing. Below 7 or 8 degrees the seed germinates poorly and, above all, the cold felt when young pushes the plant to bolt to seed instead of forming a root. So wait for a soil warmed to 8 or 10 degrees, whatever the calendar says. A sowing made too early, on ground that has not warmed, often ends in bolting.

Once established, beetroot is moderately hardy. It takes the cool of the late season and light white frosts in its stride. But a large, protruding root fears hard frost: a sharp cold at the end of autumn makes it rot in the ground. That is the signal to harvest and bring in.

Pruning and upkeep

No pruning in the strict sense, but one obligatory step: thinning. Since each cluster gives several crowded seedlings, you must step in as soon as the plants have two or three true leaves. Keep the most vigorous at each spot and remove the others, so as to leave one beetroot every ten centimetres along the row. Without this sorting, you harvest tiny, deformed roots that get in each other’s way.

Routine care comes down to little: hoe and weed between the rows to keep the soil clean and airy, and maintain the mulch. The young thinned leaves are not thrown away, they are eaten like spinach, raw as baby leaves or cooked.

Pests and diseases

Beetroot is little prone to disease. The most common in a humid climate is cercospora leaf spot, a fungus that pits the leaves with small round spots with a grey centre and reddish edge, in mild and damp late-season weather. It disfigures the foliage without destroying the root; remove the affected leaves and avoid watering the leaves in the evening.

As for pests, watch for the beet leaf miner fly, whose larva mines the inside of the leaves and digs translucent galleries in them that turn brown. Crush the affected areas between your fingers and remove the very affected leaves. Slugs attack the young seedlings in spring, the most at-risk period, before the plant gains strength.

Propagation

Beetroot is multiplied by direct sowing, and only that way in the kitchen garden. Sow the clusters in place every five centimetres in a furrow, then let them come up before thinning. Soak the seeds a few hours in lukewarm water before sowing: the hard coat of the cluster softens and germination gains several days.

Producing your own seed takes patience, because beetroot is biennial: it flowers only in its second year. You would have to keep a few fine roots in the cellar over winter, replant them the following spring and wait for the flower spike. In practice, you buy fresh seed each year, it is simpler and more reliable.

Toxicity

Beetroot is entirely edible, root and young leaves alike, with no known toxicity for humans. Like spinach, it contains oxalates, a moderate point of caution for people prone to kidney stones, reduced by boiling. Do not be surprised if urine or stools take on a pink tinge after a beetroot meal: this harmless phenomenon, caused by the vegetable’s betalain pigments, affects about one person in ten and signals nothing abnormal.

Month-by-month care calendar

Green Hub tips

• Never forget to thin. Each seed is a cluster hiding several: without sorting, you harvest roots the size of marbles.
• Do not sow on ground that is still cold, below 7 or 8 degrees. Cold soil pushes beetroot to bolt instead of forming a root, whatever the calendar says.
• Water regularly, without swings. A beetroot that goes thirsty then drinks all at once turns hard, splits and develops fibrous rings.
• For winter, store the roots in the cellar in a box of barely damp sand, leaves cut to two centimetres: they last until spring.