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Planting mustard in autumn: how to grow, care for, harvest the healthy green manure in the garden!

Growing mustard may be unfamiliar to many gardeners, but this spicy green is quick and easy to grow. Mustard (Sinapsis Alba) is a fast growing green manure that can be sown from March to September. It has a growing season of 1 to 2 months and can reach a height of 60 to 90 inches. This semi-hardy annual will grow in most soils, but prefers fertile soils. In dry periods, supplemental watering may be required. It is excellent for gardens and containers in both spring and fall. By planting green manure in your garden, you can add a healthy and tasty food to your vegetable harvest. Read on to learn how to plant and care for mustard.

Table of Contents

How to plant mustard

Planting mustard in autumn - how to grow, care for, harvest the healthy green manure in the garden!

Mustard is planted either from seed or from seedlings. Because growing mustard seeds from seed is so easy, this is the most common way to plant mustard seeds. However, young seedlings work just as well. If you are growing green manure from seed, you can sow it outdoors three weeks before the last frost date. If you want a consistent harvest, sow mustard seeds about every three weeks for a successive crop.

Mustard grass does not grow well in the summer, so you should stop seeding near the end of spring and start again in mid-summer to harvest in the fall. When sowing mustard seeds, plant each seed just below the soil, 1 inch apart.

Improve the native soil by mixing in a few inches of old compost or other rich organic material. After the seeds have germinated, thin the seedlings to 8 inches. When planting seedlings, space them 8 to 13 inches apart starting three weeks before the last frost. If you are sowing mustard seeds, you can plant new seedlings every three weeks for a continuous crop.

Care for green manure

Mustard is planted either from seed or from seedlings in the garden or in containers

Mustard seeds in the garden need little care. Give plants plenty of sun or partial shade, and keep in mind that mustard grass likes cool weather and grows quickly. You can fertilize with a balanced fertilizer, but this is often not necessary in a well-worked vegetable garden soil. Mustard grass needs 5 inches of water per week. If you don’t get that much rainfall per week when growing mustard, you can water extra. With a regular water supply, the green manure can quickly produce edible leaves.

If the plants grow under stressful conditions such as drought or heat, the leaves can become unpleasantly spicy to most tastes. Keep the soil evenly moist. Keep your mustard bed weed-free, especially if they are small seedlings. The less competition they have from weeds, the better they will grow. Mulch with wheat straw to keep the plants moist. It takes about 10 to 12 plants to supply two people with fresh greens, plus some to freeze and use in warmer weather.

When to harvest mustard grass

Mustard vegetables tolerate frost and short temperature drops, but are susceptible to heavy frost

You should harvest mustard grass while it is still young and tender. Older leaves become tough and increasingly bitter as they age. Discard any yellow leaves that appear on the plant. Mustard tolerates light frost, which makes its leaves sweeter. In areas where there are no killing frosts, gardeners can grow mustard throughout the winter. The mustard bed is a beautiful sight in the cool season garden. The leafy plants are easy to care for and pair well with fall flowers such as pansies. Mustard grass grows in a rosette of leaves that grows up to three feet tall. You can cook the large, peppery greens or pick smaller, young leaves to eat raw in salads and on sandwiches.

Keep your mustard bed weed-free, especially if they are small seedlings


There are two ways to harvest greens. You can harvest only the large, outer leaves so the center will continue to grow and produce more greens. Or, you can treat the plant by cutting all the leaves to within 8 to 10 inches of the ground and letting the stump continue to grow. Remember that young leaves have a milder flavor for salads. Mustard vegetables can tolerate frost and short temperature drops, but are susceptible to heavy frost. Like other vegetables, their flavor becomes sweeter with cold.

When the weather warms in summer, the green manure sprouts a flower stalk and forms yellow flowers. The plants should be uprooted at this time, but the flowers make a beautiful arrangement. In colder climates, you can plant mustard in a greenhouse covered with a film to protect it from severe frost. This greenery is grown in the back, while the kale grows in the front.