Plant health, moisture retention and proper drainage are all achieved by choosing the right ingredients to fill your raised bed vegetable garden. Add the soil ingredients in layers. Mix and water at regular intervals as you fill the beds.
One quarter of your soil mixture should be garden soil. You can purchase it in bags from a garden centre or in larger, bulk quantities from soil and gravel dealers. Quality garden soil supplies basic nutrients and a coarse particle size to help with drainage.
Composted organic material should be a quarter of your mixture. Use a blend of composted manure, composted wood products and humus from composted leaves and vegetation. Purchase different types of compost and mix them together before adding them to your soil.
Peat moss aids water retention and root growth. Use peat moss as a quarter of your soil mixture. Buy it in compressed bales then cut them open and break up any compressed clods that may have formed before adding them to the raised bed.
Coarse, agricultural-grade vermiculite is the final quarter of your soil mixture. Asbestos-free vermiculite is available from most nurseries and garden centres. If not available, substitute with perlite. Vermiculite aids water retention and its larger particle size aids drainage.