Molokhia Problems: Flea Beetles, Spider Mites, Nematodes and Cold Damage

The seedling stage is the dangerous one

A grown molokhia plant shrugs off almost everything. Seedlings do not. In the two or three weeks between emergence and the fourth true leaf the crop is vulnerable to flea beetles, damping off and simple drying out, and losses at that stage are the main reason a row comes out thin.

Flea beetles are the usual culprit. They chew small round shot-holes through the leaves and can strip a seedling faster than it can grow. On a plant with six leaves this is cosmetic; on a plant with two it is fatal. A floating row cover laid over the bed from sowing until the plants are six inches (15 cm) tall solves it completely, and can be taken off once the plants are growing faster than the beetles can eat.

Damping off shows as seedlings toppling at soil level with a pinched, dark stem. It follows from sowing too thickly into cool, wet soil. Warm soil, thin sowing and watering in the morning rather than the evening prevent it; nothing cures a seedling once it has gone over.

Spider mites, the hot weather problem

The conditions this crop loves are the conditions spider mites love. Hot, dry, still air with dusty foliage produces an infestation quickly, and because the mites work on the undersides of leaves it is usually well established before it is noticed. Look for a fine pale stippling on the upper surface, leaves that feel gritty, and eventually a faint webbing in the leaf joints.

The response that works here is one most crops do not allow: cut the plant back hard. Taking the top growth off removes the bulk of the population in one action, and the plant regrows clean in a fortnight. Bag and dispose of the cut material rather than composting it near the row.

Prevent the next outbreak by keeping the soil moist and mulched, and by hosing the undersides of the leaves in the evening every few days during a hot dry run. Mites do badly in humidity. Avoid broad-spectrum insecticides entirely; they kill the predatory mites that were quietly holding the population down and the rebound is worse than the original problem.

You are picking this crop every week or two, so anything you spray is on food within days. Physical measures such as hard cutting, hosing, row cover and hand-picking are the right tools here, not sprays.

Root-knot nematodes and soil-borne trouble

In warm soils, root-knot nematodes are the problem that quietly reduces this crop year on year. Above ground it looks like poor growth, a plant that wilts in the afternoon despite watering and never puts on size however much it is fed. Pull one up and the roots carry knobbly swellings along their length rather than clean fibrous strands.

There is no rescue for an affected plant. Pull it, take the roots out of the garden, and do not grow it or another susceptible crop in that bed for three years. Adding organic matter and keeping the soil covered helps the soil biology that keeps nematode numbers down.

This is the single strongest argument for keeping a note of where the row was each year. Nematode damage builds slowly enough that memory alone is not reliable, and a simple bed sketch is enough to keep a rotation honest.

Cold, and knowing when the crop is over

Cold ends this plant rather than damaging it. Nights below 50F (10C) stop growth and yellow the lower leaves; the first frost blackens the whole plant in a single night. There is no protection worth setting up for a crop that is by then also flowering and setting pods.

The right response is to take a final full harvest while the leaves are still good, blanch and freeze what you cannot eat, then clear the plants. Waiting to see whether it survives a cold night costs you the last harvest and gains nothing.

Clear thoroughly. Pull the plants, pick up any dried pods that have shattered onto the ground, and compost the stems. A tidy clear-up keeps toxic pods out of a food garden over winter and leaves the bed ready for something hardier.