Rhubarb is one of the most popular vegetables to grow in your own garden. The popular stalks of Rheum rhabarbarum can be processed in many ways and, depending on the variety, the yields are extremely high. An advantage of the plant is the possibility of cultivating it in a raised bed or pot. Due to the specific characteristics of these cultivation forms, you have to approach aspects such as location differently.
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Plenty of space for rhubarb in pots and raised beds
In order to cultivate Rheum rhabarbarum in containers such as plant pots or raised beds, you have to consider one very specific point: the space required by the plant. Rhubarb likes to spread even outdoors. If the plant is not given enough space, this will have a negative effect on yields. The knotweed plant (bot. Polygonaceae) needs much longer in a small space until the stalks are edible. This can lead to a later harvest time. At the same time, the height of the harvest is reduced as the length of the stalks suffer from the extended ripening period. For a copy you need:
- at least 1 m²
- up to 4 m² (depending on variety)
For this reason, only small varieties such as ‘Barbara’ or the dwarf rhubarb ‘Lowberry Lilibarber’ are usually suitable for planting in containers. Compared to the fast-growing varieties such as ‘Goliath’, these reach significantly smaller dimensions and are therefore ideal for planters. Raised beds, on the other hand, can theoretically be planted with any variety, as long as it is large enough. Before purchasing the seed, compare the space requirements of the corresponding variety.
location
Rhubarb needs the same location in the bucket or raised bed as specimens planted outdoors. That means you need a location with lots of sun. It doesn’t have to be too sunny, as the plant prefers a slightly moist substrate and too sunny a spot would quickly dry out. Potted plants in particular have to deal with this problem. The following amount of light would be ideal:
- sunny throughout the day
- little midday sun
Depending on the selected pot, the location should also be protected from the wind. Although the plant can withstand rough spots quite well, in the worst case the planter cannot. This does not have to be taken into account with a raised bed. Choose a section of the bed for the rhubarb that gets enough sun. Direct shade keeps the poles thin and small. Light shade is tolerated, while partial shade could also result in low yields.
In order to offer the plant enough warmth in the tub or raised bed, you should place it in front of a wall that faces south.
Substrate
Choosing the right substrate is essential when cultivating Rheum rhabarbarum in tubs or raised beds. Because rhubarb is a hungry crop, you need to ensure there are enough nutrients in the soil early in the season. At the same time, the structure must fit so that the heavy plants can establish themselves effectively, which has a positive effect on growth. The substrate should have the following properties:
- nutritious
- profound
- not too loose
- well ventilated
For this reason you should mix the substrate yourself. The following soils are suitable for this:
- high-quality garden soil
- potting soil
- herbal soil
It is important to improve the drainage of the substrate so that there is no waterlogging. Simply use a little sand mixed with the soil. The sand ensures that the substrate receives structure. A little clay can’t hurt here either. At the same time, it is important to enrich the substrate with nutrients, as there are significantly fewer of these available in the bucket. Suitable for this purpose are:
- Compost
- horse manure
- Hornspäne
Do not use horse manure if you keep the rhubarb on the balcony, for example, as the odor would be too intense. For a raised bed, on the other hand, the manure is ideal. Compost and horn shavings can be used for both variants. You can then place the young plants in the container and care for them in the usual way.
maintenance
Rhubarb thrives without any help in the bed, but requires much more care in pots or raised beds. Especially with regard to the supply of nutrients and water, leafy vegetables are dependent on humans, as the vessels can only hold small amounts of them. At the same time, neglecting Rheum rhabarbarum care can increase the risk of pest infestation or disease. For this reason, ongoing care is essential if you want to harvest the spears annually. These are harvested in the same way as the specimens in the vegetable patch.
pour
Regular watering is important when caring for rhubarb in pots or raised beds. Since the knotweed needs warm and sunny locations, the substrate tends to dry out. Because of this, it is important that you water regularly and frequently. This is particularly important for rhubarb in a pot, as it has less substrate than the specimens in the raised bed. Suitable for casting:
- rainwater
- stale tap water
- Filterwasser
From May to the end of June it is particularly important to monitor the water balance of the plant. Always water a little more during dry periods. There is no prescribed watering frequency. As soon as the top layer of soil has dried, you must water at the latest.
Fertilize
Nutrients are even more important for a heavy feeder like rhubarb in a raised bed or pot than in a vegetable patch. You don’t need to fertilize frequently if you do it the right way:
- fertilize in March
- use mature compost
- Menge: 3 l pro m²
- incorporated into substrate
- fertilize again after June 24th
- Use nettle manure
The second fertilization of the year is therefore carried out directly after the last harvest date for the stems. These two fertilizations give the plant sufficient energy throughout the season until autumn.
pests and diseases
If a good location has been selected and care has not been neglected, Rheum rhabarbarum will not actually become ill or attacked by pests. Aphids like to snack on rhubarb, which can be remedied with home remedies such as a shower or various sprays. Only the rhubarb mosaic virus has to be contained by removing the affected parts of the plant. This can be recognized by the following symptoms:
- Spots appear on leaves
- light to yellowish
- mosaic shape
- can merge
- leaves die off
The virus is usually introduced by aphids.
mixed culture
A mixed culture is recommended, especially in raised beds, if you want to plant Rheum rhabarbarum. The reason for this is the improved resistance to pests and diseases, as well as the supply of nutrients. Since rhubarb is a heavy feeder, the wrong neighbors can pollute the soil and destroy other plants. For this reason, you should only keep rhubarb in a mixed culture with the right neighbors in order to exploit their advantages. Suitable vegetables are:
- peas
- beans
- Spinach
- lettuce
- Kohlrabi
- Kohl
Of course, when planning the mixed culture in the raised bed, you have to make sure that the good neighbors get along with each other. A mixed culture would otherwise have a negative effect on the substrate and thus the rhubarb.
