Raised Beds (& No-Dig) Method

An important part of successful growing is to improve the fertility of the soil in order to produce better, stronger plants. One method is to use raised beds and to avoid the regular, annual digging - There isn't an absolute 'right' or 'wrong' way to use the system, adapt it to your own circumstances as you gain experience.

What is the No-Dig method? The traditional yearly routine included digging the soil during the Autumn so that Winter frost would turn the soil into a fine tilth ready to sow the next years seeds. Nowadays, once the beds have been made, the only use of a spade or fork is in the normal cultivation to grow your crops. It is also important to clear the paths of the pernicious weeds or they will start to creep back in. You will need to continue to keep the paths clear of weeds in the years ahead, but you'd want to do that anyway.

Why use the No-Dig method? Turning the soil can harm a lot of beneficial bodies in the soil, earthworms for example. To dig  risks bringing poorer soil to the surface, especially if you have only shallow topsoil and exposes weed seeds so that they can germinate, (Leaving them submerged and dormant you save  weeding). Healthy soil is vital to good plant growth. Important bacteria vital to plant growth are found only in the top few inches of the soil. If you take out a great fork-full of soil and turn it over, you destroy the very bit that helps your plants grow. Gradually the depth of this increasingly fertile soil will get deeper and your plants stronger and more productive. 

The Basics of the No-Dig Method. The plot is divided into 4 foot beds - see below for more details on this. Then well-rotted compost, horse or farm-yard manure, straw and other such materials are used to build up the fertility of the bed. The point to note for now is that this organic material will slowly compost down, and one of your maintenance tasks will be to keep adding to the bed (even whilst the crops are growing) and gradually make them deeper. Over several years they may reach a foot or more high, so many folk refer to them as 'Deep Beds'.

The crops are planted directly in the compost, not into the soil, as few gaps as possible, and the vacant space is either used for other crops or a mulch or a green manure used to cover the surface. Most people using the No-Dig method also use a crop rotation system, to ensure the best conditions for the ground and for the crops.

They can be more sophisticated with some form of edging so that the soil can be raised above the level around them to improve drainage on heavy soil and also slightly increase soil temperature earlier in the Spring. 

WHY use 4 feet wide beds? The most important feature of this method is that you must NEVER walk on the beds. If you walk on them, it destroys the soil structure and kills those micro-organisms that you're taking all that trouble to help. You'll still need to do normal maintenance on the beds - weeding and tending the crops etc. - so you'll need good access. Using 4 foot beds with a path around them, you only have to reach a maximum of 2 feet to get at the plants or weeds. This ensures that people with bad backs don't stretch too far, but the real reason is that it ensures you don't ever walk on the beds. Also you'll be adding lots of compost and manure to these beds, not just as a one-off activity but as an on-going part of the method. And compost and manure are heavy things to lift around, so again you don't want to lift them far from the path.

Planting the beds. When you have made your bed the top few inches will largely be compost and you plant or sow directly into this layer, even potatoes can be planted on the top of your compost, and then covered with straw, plastic or simply more compost. When the tips start to poke through, add more compost, and keep doing this instead of earthing them up. For  runner beans create the normal framework (with the feet well pushed down through the compost material and into the soil) and then plant the beans two inches deep in the top of the compost. Or, if you've started your runners indoors, then when the danger of frost has passed just pop the plant with it's root-ball in the compost - just the same as you would for an earth bed. How about brassicas? - well, they may need planting just a little deeper than normal as the plants grow big and heavy. However the root systems in No-Dig beds are particularly strong because of all that goodness in them, so as the plants mature there shouldn't be any problems with the stems falling over (at least, no more so than with those on earth plots).

Maintaining the beds. Keep as much of the surface of the beds covered as possible. Prevent bare spaces by planting 'catch crops' such as lettuce, spring onion etc., or plant some flowers to attract the bees, or plant green manures. If you don't want to do any of these, then apply a mulch to the bare surface.

You'll need to weed the beds. Do this regularly when the weeds are small, there will be no major disturbance to the soil in your beds. Hoeing is good provided that you don't hoe too deep. When the soil isn't in use protect it by sowings green manures like tares, buckwheat, and limnanthes (poached egg plant). Seaweed meal is good, it isn't so much a fertiliser in the normal sense, but instead raises fertility by stimulating activity of soil life, e.g. worms and bacteria. The numbers of weeds will decrease and even heavy clay, certainly becomes more friable and manageable.

Green manures in the No-Dig system. You will find more about green manures elsewhere on this website. The choice of green manure will be decided by the time of year when you want to sow, some are hardier than others, the crop that is to follow and the special attributes particular green manures have. One popular method is to precede brassicas by clover, a leguminous plant that fixes Nitrogen from the air in nodules on its roots. Since Brassicas generally require lots of Nitrogen transplanting seedlings into the clover crop is providing them with their preferred conditions. (There is a side benefit to this method - many of the pests of Brassicas are confused by the scent given off by the clover and so the Brassicas suffer less pest damage too.)

Crop Rotation in the No-Dig system. Rotations help prevent the build-up of pests and diseases, and usually the crops follow an order that improves the cultivation and fertility of the soil and the legacy of a preceding crop benefits its successor. A common rotation pattern completes the cycle every 4 years - for any one bed, year 1 is potatoes, year 2 is peas/beans, year 3 is Brassicas and year 4 is roots/onions. All the remaining vegetables can be slotted into one of those groups and each year will accompany that family as it moves around the plot. Some people, especially in the early days keep a diary of what crops have been grown on which beds, but provided that you make sure that you don't have the same crop on the same bed for successive years you needn't worry too much if occasionally things don't go quite according to plan.

There is a school of thought that short rotations (3-5 years), although they are good for fertility, are not effective for pest control, as many pests are quite capable of surviving these periods. A random pattern with long breaks for certain crops does work well. The bed system also works better if you avoid growing members of the same family in adjacent beds as that also make the pests work harder to find their preferred food.

Right, so how do I get started? Sketch out a plan of your plot and the layout of the beds, compost heap and other fixed items like sheds. You can then begin by preparing smaller areas as the appropriate season arrives and if you're a little bit late it doesn't matter you can plant it anyway and if something comes then it's a bonus. You get into the swing of your plot and rotations as you go along and you can adjust it so much more easily because changes don't involve great big upheavals. That way you can start to plant/sow/ harvest etc. as you are ready. Begin with things that should be sown now and go on from there.

Finally, the best advice seems to be, plan out what you want to do, where you want to do it, and just go for it.