If you have only a small space in which to grow vegetables, then packing them into a raised bed full of nutrient-rich soil is the answer. What’s more, the vegetables will be easy to maintain and pick.
Whether it’s time constraints or poor health, knowing and replenishing your soil can be a hassel. Even more so if you have a small garden.
Time Saving Tips
1) Buying the frame of a raised bed in kit form will save 5-10 hours compared with making one from scratch using individually sourced components.
2) Pre-formed plastic sections that link together are even easier to install and will not rot.Their hollow construction also makes them a good insulator for the bed, encouraging your crops to grow quickly and strongly.
3) Fill a raised bed (0.75 m by 2 m) with layers of shredded branches, garden waste, garden soil and compost.
Off to a Good Start
The soil in a raised bed warms up quickly in spring because the sides catch the sun as well as the soil surface. Rotting matter such as manure that has been dug into the soil during preparation of the bed also gives off heat, which is why you can often sow and plant up a raised bed as much as two weeks earlier than an ordinary vegetable patch.
Heat-loving plants thrive in a raised bed and, at a height of 75-90 cm, many jobs can be carried out while standing. Until about mid April, the first seeds for sowing are fast-growing radishes, spinach or lettuce.
From May onwards you can plant out young cabbage, butterhead lettuce or tomato plants and cucumbers. To make the most of a raised bed, position taller plants in the centre, plants of medium-height at the sides and smaller ones at the very edges.
Easy Maintenance for Your Crops
There are various ways of keeping unwanted insects away from a raised bed: fine-mesh wire netting at the base keeps out mice and voles, and strips of tin folded back and laid along the outer edges make an excellent snail barrier.
Raised beds dry out more quickly than conventional beds and need more frequent watering. Line the insides of the retaining walls with pond liner to prevent water from seeping out quickly when watering and to help retain moisture.
The ideal time to build a raised bed is autumn, when the garden has a plentiful supply of branches, twigs and other organic matter that you can use for the various layers. Another advantage is that the soil in the bed will have enough time to settle and compact over the winter.
In the first and second year plant the raised bed with plants that have a high nutrient requirement.
From the third year onwards change to a more diverse planting of medium and low nutrient-requiring plants, followed by legumes, which will fix nitrogen back into the soil. Top up the bed each year with compost and fresh soil.
Dig it over lightly in spring and cover it with a layer of mulch in autumn. After about six years the soil will be exhausted and you will need to replace it.
Making a Raised Bed
To make a raised bed, you will need fine-mesh wire netting for the base, pond liner, thick planks of wood (Douglas fir or larch wood) for the sides and sturdy posts for the corners.
An area measuring about 1.5 m by 4 m is a good size and the finished bed should reach a working height of 75-90 cm.
Dig out the soil to a depth of 25 cm and put it to one side.
Erect the retaining walls and posts and line the insides with pond liner.
Cover the base of the bed with fine-mesh wire netting.
Begin filling the bed with a bottom layer of twigs and branches.
The next layer consists of lightly moistened paper, followed by coarsely shredded garden waste, then a layer of fresh garden waste and autumn leaves. Top off with a layer of compost mixed with the soil that was excavated.
Making Good Use of Soil Nutrients
- Year 1: The bed has a high nitrogen content. Plant plants with high nutrient requirements such as sweet peppers, tomatoes.
- Year 2: There is still plenty of nitrogen. Plant plants with a high nutrient requirements such as cucumbers, courgettes, and fennel.
- Year 3: Nitrogen content is beginning to decline. Choose to plant plants with medium nutrient requirements such as kohlradi, carrots, radishes and strawberries.
- Year 4: Even les nitrogen. Plant plants with medium to low nutrient needs such as mange-tout peas, radishes lettuce.
- Year 5: Soil now has comparatively low nitrogen. Plant plants with low nutirent requirements such as onions, carrots, radishes and strawberries.
- Year 6: The raised bed rots down and the nutrients are exhausted. Plant plants with low nutrient and nitrogen-fixing plants such as beans, peas, broad beans and potatoes.
- Year 7: Take the soil and spread it eslewhere in the garden and refil the raised bed. Repeat the same cycle, starting with year 1.
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