Planting rhubarb: when, where & how
Being easy to grow and delicious in desserts, it is no wonder that rhubarb is popular. Learn all there is to know about planting rhubarb.
Rhubarb (Rheum x hybridum) is easy to grow and, being perennial, will keep coming back year after year. A member of the Polygonaceae family, the stems of rhubarb are edible and commonly used in warming crumbles and pies. We will show you how to plant rhubarb, so it thrives for years to come.
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Planting rhubarb: how-to guide
Whether grown directly in the ground or in a pot, rhubarb generally grows trouble-free. However, to ensure that your rhubarb thrives and provides plenty of delicious stems follow our tips below.
When to plant rhubarb
Rhubarb plants are available to purchase either as dormant crowns or potted plants. Rhubarb crowns, also known as offsets, are sold from early winter until early spring for planting within this period. If you have purchased rhubarb in a pot, you can plant it out any time of year so long as the ground is not frozen or waterlogged.
Where to grow rhubarb
The best place to plant rhubarb is in an open and sunny location. You can grow rhubarb in light shade. However, limited sunshine hours can cause it to struggle and lead to a poor rhubarb harvest. When it comes to the soil, rhubarb can tolerate most types but it prefers a fertile and moist soil that is free-draining and does not become waterlogged. To prepare the ground, remove any weeds and enrich the soil with some well-rotted manure or garden compost before planting. Rhubarb plants can grow large over time. If you are growing more than one rhubarb plant, plant them at a spacing of 75 to 100cm apart to give them enough room to grow.
How to plant rhubarb
You can plant rhubarb either as crowns, potted plants or even grow it from seed. Once you have chosen how you are going to grow rhubarb, you can follow the steps as below:
Planting rhubarb seeds
Growing rhubarb from seed is cost-effective. However, patience is required as it takes a year longer to produce a harvest compared to growing from crowns or actual plants. Rhubarb seeds are best sown in spring to plant out later in autumn or spring the following year:
- Prefill a small pot or module tray with seed compost, such as our Plantura Organic Herb & Seedling Compost, as it encourages seed germination and root development
- Sow the rhubarb seeds 1.5 to 2.5cm deep either 1 per cell or 2 to 3 per small pot
- Keep the soil moist but not wet and place it in a greenhouse or on a sunny windowsill
- Once germinated, usually within 2 to 3 weeks, thin out the weaker seedlings keeping only the strongest
- When the seedlings are 5 to 7cm tall, pot them on individually using a peat-free multi-purpose compost
- Grow on undercover and water regularly until all risk of frost has passed
- In early summer, gradually harden the plants off before placing them outside
- Plant out in their final position in autumn or overwinter in a greenhouse to plant out the following spring
- Perfect for herbs as well as sowing, propagating & transplanting
- For aromatic herbs & healthy seedlings with strong roots
- Peat-free & organic soil: CO2-saving composition
Planting rhubarb crowns
Rhubarb crowns are available from online suppliers and garden centres over the winter months for planting from November until March. However, you can also divide plants in the autumn to propagate rhubarb for free. When growing rhubarb from crowns, you can begin to sparingly harvest the stems two growing seasons after planting.
To plant rhubarb crowns:
- Remove any weeds and incorporate organic matter into the soil to prepare the planting site
- Dig a hole so that when placed inside the crown tip is at soil level or just above
- Plant the rhubarb crown and backfill with soil, gently firming in as you go
- Water thoroughly to prevent air pockets around the roots
- Avoid harvesting the following spring to allow the plant to become established
Growing rhubarb in pots
If space is limited, you can also grow rhubarb in pots. However, due to the plant’s size and hungry nature a minimum pot size of 50 to 60cm wide and deep filled with a rich compost mix is advisable. Our Plantura Organic Enriched Compost is perfect for growing rhubarb in pots as it will provide a wide mix of essential nutrients to support the rhubarb’s growth. Some rhubarb plants can grow over 1m tall and wide. When growing rhubarb in a pot, you may want to choose a more suitable and smaller rhubarb variety such as ‘Fulton’s Strawberry Surprise’.
- Perfect for all crops and ornamental plants with a high nutrient requirement & for raised beds
- Improves soil quality & promotes healthy root growth
- Peat-free & organic soil: CO2-saving composition
When planting rhubarb in a pot, first add a layer of gravel at the base to aid drainage. Half-fill the container with compost and place the rhubarb crown with the tip at soil level or potted rhubarb plant so that it is the same depth it was previously planted. Backfill with compost and firm in before watering. If the soil is already fertile and rich, fertilising rhubarb in the ground is not strictly necessary. However, you can feed container-grown rhubarb with a general fertiliser in spring to help replace any lost nutrients. When the rhubarb plant appears to have outgrown its pot or its growth becomes weak, divide the plant and repot in fresh soil or plant in the ground.
Raised beds
Growing rhubarb in raised beds can be advantageous if your garden’s soil has poor drainage or is prone to waterlogging. As with growing rhubarb in a pot, you will want to provide a suitable depth of soil for the roots to grow and lateral space for the stems to develop. If your raised bed is of adequate depth and size and the soil is enriched prior to planting, there is no reason why you cannot grow rhubarb in a raised bed long term. However, smaller varieties may be more suitable and a plant spacing of 75 to 100cm is still recommended to avoid plants competing for nutrients and space.
Tip: to help conserve moisture and boost the soil, apply a mulch of organic matter in spring.
Rhubarb growing problems
Weak or spindly stems can sometimes be encountered when growing rhubarb. Caused by a lack of nutrients in the soil, not enough sunshine, overcrowding, over-harvesting or old age, weak rhubarb stems can be disappointing. Depending on the cause, you can try feeding and mulching rhubarb plants in spring, moving container plants to a south-facing spot and dividing plants in late autumn when they are dormant.
Slugs and snails (Gastropoda) are a commonly faced problem when growing rhubarb. Slugs and snails are easy to identify by how they eat the leaves, especially soft and young leaves. To reduce slug and snail numbers, pick them off by hand, lay barriers and encourage predatory wildlife into your garden.
How to grow thick rhubarb stalks?
As mentioned previously, the right care and nutrition can help encourage thick and juicy rhubarb stems. Mulching rhubarb plants with garden compost or other organic matter can help give the plants a boost and conserve moisture over the summer months. You can also fertilise rhubarb with a balanced slow-release formula in spring to support its leafy and vigorous growth.
Companion plants
Companion planting, or growing certain plants alongside or with others for their mutual benefit, is a long-practised method. Beneficial companion plants for rhubarb include beans, cabbages and strawberries (Fragaria x ananassa). However, it is not advisable to grow pumpkins and squash with rhubarb, as the rhubarb leaves can overshadow the gourds and pumpkin vines can suffocate the rhubarb plants.
For even sweeter stems, you can force rhubarb by covering the stems with a light omitting pot. Learn how and when to force rhubarb in our separate article.
