Rhubarb - Growing Your Own / RHS Gardening

Once established, rhubarb needs little maintenance, apart from removing flower stems and faded leaves, and mulching Mulch is a layer of material, at least 5cm (2in) thick, applied to the soil surface in late autumn to late winter (Nov-Feb). It is used to provide frost protection, improve plant growth by adding nutrients or increasing organic matter content, reducing water loss from the soil, for decorative purposes and suppressing weeds. Examples include well-rotted garden compost and manure, chipped bark, gravel, grit and slate chippings. in spring. Clumps should also be divided once they become overcrowded. For a crop of early, sweeter stalks, you can force (or blanch) them in winter.

Watering and feeding

Once established, rhubarb rarely needs watering, but young plants and those in containers do need regular attention:

• Newly planted rhubarb – water regularly during dry spells throughout its first growing season, until well rooted
• Established rhubarb plants – water only during prolonged dry periods in summer. Growth will slow down and even stop if conditions are too hot and dry
• Rhubarb in containers – water regularly throughout the growing season, as the compost Can refer to either home-made garden compost or seed/potting compost: • Garden compost is a soil improver made from decomposed plant waste, usually in a compost bin or heap. It is added to soil to improve its fertility, structure and water-holding capacity. Seed or potting composts are used for growing seedlings or plants in containers - a wide range of commercially produced peat-free composts are available, made from a mix of various ingredients, such as loam, composted bark, coir and sand, although you can mix your own. will dry out quickly. Keep it moist but never waterlogged Describes soil or potting compost that is saturated with water. The water displaces air from the spaces between soil particles and plant roots can literally drown, unless they are adapted to growing in waterlogged conditions. Waterlogging is common on poorly drained soil or when heavy soil is compacted. . Waterlogged compost can lead to roots rotting

Mulching Mulch is a layer of material, at least 5cm (2in) thick, applied to the soil surface in late autumn to late winter (Nov-Feb). It is used to provide frost protection, improve plant growth by adding nutrients or increasing organic matter content, reducing water loss from the soil, for decorative purposes and suppressing weeds. Examples include well-rotted garden compost and manure, chipped bark, gravel, grit and slate chippings. (see below) should provide sufficient nutrients To grow well, plants need a wide range of nutrients in various amounts, depending on the individual plant and its stage of growth. The three key nutrients usually taken up from the soil are nitrogen, phosphorus and potassium. Plants also need carbon, oxygen and hydrogen to make carbohydrates — their main energy source. Carbon and oxygen come from the air as carbon dioxide, while hydrogen is drawn from water absorbed by the roots. Other important soil nutrients include magnesium, calcium and sulphur. Most garden soils contain enough of these nutrients to support healthy plant growth. for rhubarb to grow well. If you have poor soil and growth is slow, applying a high-nitrogen, organic-based fertiliser, in spring or summer, will boost growth.

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Mulching

Every spring, apply a mulch of well-rotted organic matter, such as homemade garden compost, in a layer about 7cm (2½in) deep around rhubarb plants, but take care not to bury the crown, as that could cause rotting. Mulching Mulch is a layer of material, at least 5cm (2in) thick, applied to the soil surface in late autumn to late winter (Nov-Feb). It is used to provide frost protection, improve plant growth by adding nutrients or increasing organic matter content, reducing water loss from the soil, for decorative purposes and suppressing weeds. Examples include well-rotted garden compost and manure, chipped bark, gravel, grit and slate chippings. helps to retain moisture in the soil and suppress weed growth.

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Forcing rhubarb

Earlier harvests of sweeter, tender, pale stalks can be produced by covering rhubarb plants with a forcing Artificially speeding up a plant’s growth, flowering or fruiting, usually by manipulation of temperature and light. Rhubarb and chicory can be forced in late winter by covering with a forcing jar or bucket, or by placing potted plants in the dark, to produce earlier, paler, sweeter growth. Hyacinths and other spring bulbs are often forced, so they flower earlier indoors. jar, tall bucket or dustbin in mid-winter, so the stems form in the dark. Choose an early variety, such as ‘Timperley Early’, and only use a strong, healthy plant. Once stalks appear, they will grow quickly so check them regularly. They'll be ready to harvest four to eight weeks after being covered.

After you have harvested the first flush of forced stems, remove the covering and allow the plant’s subsequent stems to develop normally. Avoid forcing the same plant in consecutive years. For more information on forcing rhubarb, see our guide below.

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Forcing rhubarb

For an even earlier harvest, lift some roots in November. Ideally leave the lifted roots outside for up to two weeks, to expose them to more cold - this is needed to overcome dormancy Dormancy refers to a period of inactivity in plants, during which they slow down or stop their growth, conserving energy and resources. This is a natural process that helps them survive harsh conditions, such as winter or drought. Dormancy in seeds is a mechanism that prevents them germinating until environmental conditions are favourable for growth. . Then pot up with peat-free multipurpose compost Can refer to either home-made garden compost or seed/potting compost: • Garden compost is a soil improver made from decomposed plant waste, usually in a compost bin or heap. It is added to soil to improve its fertility, structure and water-holding capacity. Seed or potting composts are used for growing seedlings or plants in containers - a wide range of commercially produced peat-free composts are available, made from a mix of various ingredients, such as loam, composted bark, coir and sand, although you can mix your own. and bring into a cool room or greenhouse at a temperature of between 7-16ºC (45-60ºF). Exclude light with buckets and keep the roots only slightly moist. Stalks can usually be harvested in five weeks. Crowns forced in this manner are significantly weakened and usually discarded after harvest.

Removing flowers

Rhubarb clumps might produce flowering stems in spring and summer, these should be removed at the base as soon as they appear, to prevent them weakening the plant.It is believed that some varieties are more prone to flowering than others, and that seed raised rhubarb may have a higher likelihood of flowering. Flowering is more common in a wet summer or if a high nitrogen feed has been overused. Also, older plants that haven't been divided for many years are more likely to flower.

Dividing mature plants

Large clumps of rhubarb should be divided every five years or so, especially if the leaves are overcrowded or growth has become weaker. This will give you several vigorous new plants for your own garden or to share with friends, but only propagate from strong healthy plants to ensure they are virus-free. Dig up the entire clump while dormant Dormancy refers to a period of inactivity in plants, during which they slow down or stop their growth, conserving energy and resources. This is a natural process that helps them survive harsh conditions, such as winter or drought. Dormancy in seeds is a mechanism that prevents them germinating until environmental conditions are favourable for growth. , between mid-autumn and early spring. Use a spade or an old kitchen knife to slice it into several smaller sections, each with a portion of the rhizome (thickened underground stem) and at least one growing point ( bud A bud is a small, undeveloped shoot that contains the potential for new growth. Buds are typically found on stems, where they can be apical (found at the tip) or axillary (found between leaf axils) and may develop into leaves, shoots or flowers. ). Sections from the outer part are better than the centre of old plants. Discard any weak or decayed parts. Replant the sections straight away or wrap them in damp sacking for a short time if necessary.

Overwintering

Rhubarb is hardy and needs no protection over winter. In fact, exposure to cold is necessary to trigger new growth in spring. In autumn, allow the leaves to die back naturally, then cut or pull them all away to expose the growing points to winter cold. The faded leaves can be added to the compost Can refer to either home-made garden compost or seed/potting compost: • Garden compost is a soil improver made from decomposed plant waste, usually in a compost bin or heap. It is added to soil to improve its fertility, structure and water-holding capacity. Seed or potting composts are used for growing seedlings or plants in containers - a wide range of commercially produced peat-free composts are available, made from a mix of various ingredients, such as loam, composted bark, coir and sand, although you can mix your own. bin – there’s no need to worry about the poisonous oxalic acid they contain, as this breaks down during decomposition.