Q: What is the advantage of using raised beds?
A: Raised bed vegetable gardening has many benefits especially for small scale urban or allotment growing because of their ability to produce large harvests from a relatively small space. Raised vegetable beds can simply be mounds of soil separated by paths or can be enclosed timber planters built to the required height.
The idea behind raised beds is the soil is never walked on but accessed by the adjoining paths. The soil remains light and open making it easy for roots to penetrate while also providing air spaces for movement and respiration of beneficial soil life. It is the beneficial life in the soil which converts organic matter (manure, compost etc…) into nutrients which are then feeds your plants.
Timber raised garden beds can be used on a site with poor soil to raise the soil level and give more rooting depth for your crops. Raised planters can also be placed on hard surfaces like concrete or asphalt as long as the depth of soil in the planter doesn’t exceed the rooting depth of the crops you wish to grow.
Drainage is improved with raised bed systems meaning over wintering root crops like carrot and parsnip can be left in the ground without fear of rotting in damp winters. The improved drainage and timber sides exposed to the sun also means raised vegetable beds warm quicker in the Spring meaning you can start your crops a little earlier.
By adding deep mulches of organic matter in the Autumn and early Spring and not digging raised beds you will vastly reduce weed problems and build a very fertile soil. Digging soil brings dormant weed seeds to the surface where they germinate while mulching helps suppress weeds and keeps tedious weeding to a minimum. A fertile soil rich in organic matter means you can grow almost any vegetable crop without using any added fertilizers.
A: Begin by measuring the growing area and make a rough sketch plan. Remember you will need paths of at least 45cm wide for access which is wide enough to allow a wheelbarrow to pass. Don’t be tempted to reduce the width of paths as access can become difficult when crops are fully grown.
The best width for raised beds is 1.2m which gives a generous width while still making it possible to reach the centre of the bed from both sides. You will also need to walk around your beds to get to the other side so we don’t recommend making them over 1.8m in length. Of course you can build a run of beds over 1.8m, just leave a path between each section. Remember the idea is to never walk on your raised beds so easy access is very important.
Raised beds can be made from a variety of materials from timber raised bed kits to slab, block or stone enclosures. We don’t recommend the use of reclaimed railway sleepers as the creosote in the wood can leach into the soil and contaminate your crops.
We believe treated timber raised beds are the most versatile as they are quick and easy to assemble, last for years and can be built in an endless variety of shapes and sizes. We also supply raised beds on legs for those with difficulty bending so vegetable gardening can still be enjoyed by growers of restricted mobility.
We supply a broad range of timber raised bed kits to satisfy any budget or design which are all available on our website. For more information on our raised bed range please click on the links below.
Budget Classic timber raised beds
Mid range ‘Premier’ timber raised beds
Top of the range ‘Deluxe’ timber raised beds
Easy assemble beds – no tools required
Easy access beds – timber raised beds on legs
A: If the beds are being placed on a hard surface use a lining material to avoid particles of soil escaping from around the base of the bed. A semi permeable material like ‘Mypex’ weed block fabric is ideal as it will let water through the weave which avoids waterlogging in wet weather.
If the bed is to be placed on a grass area we recommend digging the grass covered sod in the base of the bed and inverting it so the grass is face down. We don’t recommend using a liner on soil or grass as it is beneficial to allow roots to access the soil below and to allow earthworms to move up into the bed from below.
If the raised bed is to be placed on ground with many deep rooted weeds place thick layers of old newspapers in the base of the bed at least 2 full editions deep. The newspaper will rot down over time while killing the weeds below.
A: Raised beds are a great opportunity improve the quality of your soil. If the soil on your site is poor or you are building beds on hard surface make sure you buy in the best quality you can afford. Ideally you should use a vegetable soil mix which is high in organic compost (not peat) so get your crops off to a good start. As a rue of thumb the darker the soil the more organic matter it contains so avoid light colour soil especially of a sticky clay consistency.
To give an idea of volume a raised bed 1.8m by 1.2m by 23cm high will take half a cubic metre to fill. This is half of the large ‘1 tonne’ bags normally used for delivering bulk products like soil, bark, and gravel. People often underestimate the amount of soil needed to fill a bed so it’s worth checking before buying multiple beds.
A: Once the raised beds are finished and filled with soil than most of the heavy lifting is done. Maintenance should be quite easy because you have a nice light soil structure which is easy to pull weeds out of and the higher working height makes the bed easier to look after. As we’ve said try to avoid digging as it brings weed seeds to the surface, add thick layers of organic matter to the surface instead and let the worms work it into the soil. A mulch has three jobs, it will smother the weeds, add fertility and improve soil structure making your soil more healthy and able to support your crops.
An organic mulch refers to a layer of garden compost, spent mushroom compost, well rotted animal manure (not carnivores) and bagged municipal compost made from recycled green waste. Raised beds are economical when adding mulch as all the material is focused on the beds rather than being wasted on the paths.
For the first few years expect a number of weeds to germinate in the bed which should be hoed off and disposed of. Provided the weeds are removed when small and not allowed to seed numbers will decline dramatically over a year or two. Also, if you avoid digging the soil no new weed seeds will be brought to the surface to germinate resulting in minimal weeding after a period of time.
When harvesting crops try to disturb the soil as little as possible (apart from potatoes where you have no option but to dig), add more organic matter and you are ready to plant again. The numbers of earthworms will increase as you feed them which will further improve your soil structure by mixing the organic matter through the soil, fertilizing with their waste and creating air pockets as they move around.
Q: What about crop rotation?
A: If growing in a small area full scale crop rotation isn’t really practical but it is important you keep and eye on the main crops which suffer from soil problems, potatoes, brassicas and onions. Ensure members of these vegetable families don’t grow in the same raised bed for at least 3 seasons. For more information on crop rotation including an easy graphic on the vegetable families please click the link above. You can also watch our video on crop rotation by clicking through to our you tube channel.