Growing Vegetables in Raised Beds

Raised beds are also known as deep beds, and though organic gardeners didn’t invent them they know the true value of them.

For large or small gardens, for vegetables, flowers or a mixture of both, deep beds are ideal. You’ll be surprised what you can grow in it.

They are usually double dug when they are first made, so as to give a good depth of workable soil.

Advantages of raised beds for vegetables

• space is used efficiently as there is more growing space in small plots
• no soil compaction as you don't walk on the bed
• good soil structure easy to maintain
• less digging once beds have been made & forking before planting often all that is needed
• good drainage through deep soil
• all-weather access -  walk on paths not sticky soil
• easy access to crops from both sides

Disadvantages of raised beds

• deep beds drain well and are excellent for overcoming waterlogged Northern Irish soils so keep newly sown seeds and seedlings well watered as the excellent drainage can dry the soil too quickly before seedlings have germinated and established
• a few crops not particularly suitable - eg potatoes which need ridging to stop tubers going green
• a lot of physical effort is needed to make them (but it's worth it)
• tall plant supports more difficult - eg runner beans as no firm soil to put stakes in

Suitable edging materials

• old wooden boards - eg old floor boards, but they rot eventually
• concrete building blocks on edge - durable, relatively cheap, but very heavy to install
• old roof tiles or slates
• old bricks on end
• logs -  will rot eventually

 

Suitable path materials

Space beds about two feet apart to allow access paths .

• grass - needs regular cutting - making sure your lawn mower can get between the beds
• straw over thick newspaper - needs regular renewal
• bark, sawdust or shavings - needs regular renewal
• gravel - needs edging to beds - expensive
• slabs, bricks - expensive
• landscaping fabric - unattractive - best with bark covering

When is the best time to make a raised bed ?

• during autumn, so that the soil can be weathered by frost to give a good tilth

or

• in early spring once the soil is dry enough to walk on and dig

Making a raised bed by double-digging

Double digging is best for medium to heavy soils, where there are a lot of weeds or large stones, and particularly when the bed is being made in a lawn or other grassland.

1. mark out the position of the bed accurately

2. remove any turf or vegetation, put to one side and then bury it in
    the bottom of the bed as you proceed to dig it (not perennial weeds though)

3. working across the bed, dig out soil to a single spade's depth
    (removing any stones and perennial weeds as you go) and place it to
    one side

4. loosen the next spade depth down with a fork, removing any stones and
    perennial weeds as you go

5. fork well-rotted manure or compost into this loosened soil

6. dig the next top spit of soil (removing any stones and perennial weeds
     as you go) and place onto the loosened and manured soil

7. fork manure or compost into this replaced top spit of soil

8. repeat steps 4-7, working down the length of the bed

9. when you get to the end of the bed replace the soil which was set aside
    and add manure or compost

That’s the last digging you’ll do. It will only need forking in future years. Even our old friend scutch (couch grass) will now be relatively easy to remove.

 

Making a raised bed by single-digging

Single digging will probably suffice on light, free draining soils as long as there isn't a layer of compacted stones in the top soil.

1. mark out the position of the bed accurately

2. remove any turf or vegetation, put to one side and then bury it in
    the bottom of the bed as you proceed to dig it (not perennial weeds though)

3. working across the bed, dig out soil to a single spade's depth
    (removing any stones and perennial weeds as you go) and place it to
    one side

4. fork well-rotted manure or compost into the trench

5. dig the next spit of soil (removing any stones and perennial weeds as
    you go) and place onto the manure/compost layer

6. fork manure or compost into this replaced top spit of soil

7. repeat steps 4-6, working down the length of the bed

8. when you get to the end of the bed replace the soil which was set aside
    and add manure or compost

Feeding organic raised beds during the growing season

• fork in manure or compost every spring

• mulch around plants with well rotted, sieved compost or manure
• spread a mulch of  grass clippings around plants once they are established. They will dry to a nice brown colour, keep weeds down, and feed your plants as they rot down. Two such mulchings will last the whole growing season.
• liquid feed as required using home-made feed
• apply organic ‘fertilisers’ 
• grow a short term green manure crop between vegetable crops

•  

Putting beds to sleep for the winter

• remove crop residues and weeds, and compost them
• mound the soil up away from the edges of the bed
• cover the soil with old carpet or black polythene weighted down with stones or bricks

alternatively

• sow an overwintering green manure if you are sure it will establish properly at that time of year

or

• mound the soil up and cover with a light cover of manure or compost, topped off with grass clippings

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After very heavy rain, this newly made deep bed (this time without side walls) flooded during the winter in my level, slow draining garden. It was fine in the spring.

Feedback or queries : E-mail to Adrian

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