Pop quiz hot-shot: What is the one thing that you can add to your garden that will allow you to grow anything, no matter what kind of soil you’re sitting on?
Raised beds of course!
These let you to exercise absolute control over the growing medium in your garden, allowing you to propagate rhododendrons and roses within mere feet of each other. As you may know, these two particular species of plants prefer soils that are on polar opposite ends of the pH spectrum if they are to thrive.
The sheer flexibility offered by multiple raised beds opens up endless possibilities.
To begin with, because you need to fill the raised beds with new growing medium (eg soil) and fertiliser, you could create a delicious root-growth zone as deep as the bed itself. The deeper the better, as this would support vigorous growth in everything from trees to root vegetables.
And with depth we gain volume, which allows for less-frequent watering than pots, as the ratio of soil-to-root is higher and therefore more moisture is retained for longer.
Even with all of this moisture retention, the raised beds will be better drained than the regular beds around it (unless you live on the beach). This means the soil temperature will increase faster during springtime –which means earlier germination for your seeds.
And to top it all off, as the beds are raised above floor height, they are many times more convenient to work in, especially if you have mobility problems or even just an occasional bad back. There are even raised beds for sale designed to have wheel chairs pushed right up to them.
Building raised beds
Now that I’ve convinced you, here are some pointers to consider when building them:
- Do not make them too wide. If you can access the raised beds from both sides, make sure you can reach the middle easily. If only from one side, make sure you can reach all the way across.
- Do not build them where they block access points. But, on the other hand, you could build multiple large raised beds to dictate new pathways and block areas off as needed.
- The larger they are, the thicker the wood will need to be. For low-down raised beds no higher than 15cm, 2cm wide gravel boards will be fine. Any higher, then I would be looking at using timber as thick as up to 12.5cm depending on the situation.
- A sure fire way of preventing the wooden panels bowing out from the weight of the soil behind, is to hammer in on the outside face wooden stakes as deep as the height of the raised bed. One of these for every 3ft of panel will do. If the wood used is thicker than 5cm (such as oak sleepers) than this is not a problem.
- Materials: the pressure-treated timber you can buy these days is perfectly safe, but I would not recommend painting it with extra preservative, as you would be introducing harmful chemicals into the soil. If you do, use a water based one, and leave the timbers to dry in the sun for a day or more to be sure the preservative has been properly absorbed. What you really need to watch out for are ‘reclaimed’ sleepers. These were originally used in industrial and locomotive environments, and are full of tars and other toxins. Not to mention they smell when in the hot sun.
- Remember to leave enough room between the raised beds and in the corners to move around in! 60cm is wide enough for a wheel barrow.
- You can use other materials to construct your rais
ed beds. If you use bricks or breeze blocks, remember to leave seep holes near the bottoms of the walls to let excess water out.
There are easy-to-assemble kits available from garden centres and the like, but where’s the fun in that? Of course if you’re not able to build the raised beds yourself – just ask, we’re more than happy to build them for you – to interesting shapes too!
If I have inspired further questions or simply confused the heck out of you, please contact me via our website.