Raised Bed Gardening - Part 1: How to Build Raised Beds?

Three years ago we decided to build raised beds to give us a better chance of success with growing our own vegetables and we have never looked back since! Building the raised beds is actually really easy to do, and very much worth the effort. Growing vegetables in the raised beds saves so much time in the long run and is generally more efficient too. So if you're not the one to shy away from a small DIY project, this one is definitely worth it! It will only take a day or two to complete.

Why Build Raised Beds?

When we first bought our house, we attempted to grow vegetables without raised beds. Not only we had very little knowledge about gardening, we were actually doomed from the get-go due to poor soil quality and a constant battle against weeds and aphids. Today we ask ourselves why we didn't start raised bed gardening earlier. If you've ever wondered why people bother with making and using raised beds, here are some of the many benefits:

• Longer growing season - allowing you to plant earlier in the season and enjoy vegetables way into the winter.
• Easy to maintain and fewer weeds - It really does save so much time and let's face it, who enjoys weeding?! The only maintenance raised beds need is watering frequently if the weather is dry.
• Improved drainage and soil structure - Important for a wet climate as the soil doesn't become saturated and also stays aerated.
• Better for your back, especially if you go for a higher bed structure.
• They look great! - They can be as neat as you want them to be and even become a feature you can be proud of. We have surrounded our three raised beds with Welsh slate chippings and we think they look wonderful!

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Before Starting:

Before you start building your own raised beds, there are a few things to consider, as without the correct location and soil it will hard to get things growing, no matter how hard you try!

Location: Although a lot of vegetables can grow in both sun and shade, if the area doesn't get any sun it's going to be very limiting for a lot of vegetables. So ensure your bed is in a position where it will get plenty of sunshine. It's worth checking the area during a sunny day for shadows from trees, houses or fences and estimating how many hours the patch gets daily. Deciding on the location will also determine the size and shape of your raised beds.

Soil/Compost: We went for all-purpose compost and coupled with it with a few bags of manure and this has been working really well for us. We just top it off with some more compost and natural fertiliser each year and turn over the soil to keep it aerated. Do not fill your beds with any soil though - it may be full of stones, weeds and generally not of great quality. Invest in some good compost and you won't regret it. Once you've worked out the size of your raised beds, you can easily calculate the amount of compost/ soil you will need to fill: simply multiply the length, the width and the height of your beds to get the volume you'd need to fill your beds to the brim.

Materials and Equipment Needed to Build Raised Beds:

In this section, I will right down everything we bought and used to make our raised beds from scratch. We live in the UK, and bought most things at Wickes and Amazon. Building raised beds requires only some very basic tools and equipment that we already had.

Materials:

• Wickes Treated Kiln Dried C24 Timber - 45mm x 195mm - or similar, for the main structure of the raised beds. We recommend dried/treated timber for longevity. Scaffolding planks also work well. Whatever you use, make sure they are thick enough to last.
• Wickes Treated Kiln Dried C16 Timber - 45mm x 95mm - or similar, for the legs of the raised beds.
• Eco Wood Treatment 4.5 Litres - Safe natural wood treatment which won't contaminate the soil, also gives a nice weathered look.
• Weed matting - We opted for Ground Master Heavy Duty Weed Control Membrane. You can get it on Amazon in various sizes depending on how large the area you need to cover. Note that you will need a bit more than the exact area you are covering. You will use some to line the inside of the bed edges to avoid the soil spilling from underneath.
• ANSIO Garden Pegs - We got a pack of 100 on Amazon to set the weed matting in place under the raised beds.
• Wickes Decking Screws - No 8 X 76mm
• Wickes 20mm Galvanised Extra Large Clout Nails - 400g
• Compost: see details above.

Equipment:

• Drill/ Cordless driver + 3mm drill bit & star/Torx bit (Bit may already come with decking screws. We've used Bosch for years, but we would definitely recommend going cordless such as this.
• Suitable handsaw/ circular saw/ chop or mitre saw
• Tape measure
• Spirit level - We never realised how useful a long spirit level could be until we got one! can be used to ensure the ground is level and the raised beds too.
• Combination square + Pencil
• Clamps: we recommend Irwin.
• Large old paintbrush
• Rubber mallet / or hammer with an old piece of wood
• Knife

Step-by-Step Process: How to Build Raised Beds?

• Level out the ground, remove any weeds and large rocks/stones: As you can see from the first photo, it's not surprising why we had issues growing vegetables with all those weeds constantly competing for sunlight and water! The first steps we took were:
  • Removing any weeds and large stones.
  • Ensuring the ground is flat and partially compacted will help to set the beds up flat in position.
  • Covering the area with weed matting and pegging it down securely. Make sure you save some weed matting for lining the edges of the raised beds to prevent the soil from spilling from underneath the beds.

• Measure out the size of the raised beds (outer edges)
  • Ensure they are not too large, as you will need to be able to reach into all areas of the bed without stepping or leaning on the soil. Generally speaking, if you can access the raised bed from two sides along the length, don't make it more than 1.4m wide, and if it's against the wall, make sure it's not more than 0.7m wide.
  • If making multiple beds leave enough space between them to be able to walk and kneel down to work in the beds.
• Order enough 45mm x 195mm timber to cut out your required lengths for the mainframe
  • We found this a good height, but you may want to go higher, especially if you have mobility issues or want to grow long root vegetables, like carrots. Note that taller raised beds will require a lot more soil.
  • Make sure you order the lengths of timber that fit with the dimensions of your beds best to make sure you are left with as little scrap as possible.
• Order enough 45mm x 95mm timber to cut out 1 leg for each corner. 
  • We used about 1.5x the height of the frame for each leg (300mm). So that attached leg sticks out ⅓ of the total length at the bottom.
• Cut timber for the mainframe to required lengths 
  • Timber may have some splits and warpage, where possible cut the long sections from the straight areas and leave split ends in off-cut areas.

• Cut a point or wedgeinto each leg section 
  • Make sure this is only done on the section below the main frame.
• Once all timber is cut lay it out and coat with Eco Wood Treatment as per instructions
  • As we had so much we did a few coats using an old brush.
  • We also used a bucket to dip the ends of each too where the end of the wood grain is exposed. 
  • Leave to dry. Over time this treatment gives a nice weathered look.
• Dry assemble the mainframe 
  • Assemble on a flat surface. If not, use a spirit level and spacers under each corner to keep it flat, it will make assembly much easier.
  • Mark up for drilling pilot holes for two decking screws per corner. This will reduce the chances of wood splitting.
  • You may need a second pair of hands to hold the corner assembled before drilling through to ensure good alignment.
• Assemble each corner with decking screws:

• Assemble and attach legs onto main frame
  • Clamp legs into each corner, drill pilot holes and then attach with decking screws
  • These give additional stability and strength to the frame together with helping to set frame level on the ground.

• Move the frame over to where it will be installed:
  • Cut a cross in the weed matting under each leg using a knife.
  • Check the bed is flat to the ground with a spirit level while hammering each corner into the ground through the weed matting. Use a rubber mallet or piece of wood as to not damage the timber. You can also put weight on the corners with your feet which can work well.
  • Ensure the frame is as close as possible to the ground, but also flat. Don't worry if some areas have a small gap when it's all level. 
• Cut strips of weed matting and attach with clout nails to the inside overlapping onto the weed matting below
  • We found this is a good way to contain the compost if there is a small gap around the bottom of the bed in some areas.

• It's now ready to be filled with compost
  • To work out the required compost amount determine the volume (Length x Width x Height in Meters) and use this to estimate the amount you need in litres, the usual unit of measure for compost. Or just use a calculator online.
  • Never step on the compost, this will ensure it stays aerated.
• It's now ready to plant!

If you have any questions or planning to build DIY raised beds, drop us a comment below and we will do our best to answer any questions! Happy growing!