Raised garden beds can make gardening easier and more accessible. They can also be helpful for giving you greater control over soil conditions and drainage, especially if you have difficult in-ground growing conditions, like our current heavy clay soil. The downside to control is that is comes with the need for more maintenance than naturalised plantings, so let’s take a look at options for refreshing and improving raised garden bed soil for replanting.
Different Types of Raised Garden Beds
Before we dig into our soil refresh, it’s important to note that different types of raised garden beds will have different degrees of access and options for soil amendment. Temporary plantings, like our raised vegetable gardens, can be dug over and refreshed as the garden cycles through removal of spent plants and preparations for replanting with new seeds or seedlings. They’re the focus of this post.
Permanent plantings are trickier. For example, all of our fruit trees are planted in slightly raised garden beds, with the upper portion of their root ball in the bed for some protection against our clay soil and the lower in the natural soil for access to a wider expanse of soil space, nutrients, and water. You can see them in the frosty photo from our first winter in the new garden below. Beds with permanent plantings, like these, can’t be dug over for amendments without disturbing the roots. Top dressing or other less invasive supplements are better suited.
Filling a New Raised Garden for First Planting
What to use when filling a new garden bed depends on the depth of the bed and what will be planted in the bed. If you have a planter that’s raised well above the root depth of your plants, you can save on quality soil by prefilling the bottom with compostable materials, lower quality soils, or other suitable/safe materials. For example, in our super deep raised veggie beds, I used a combination of compostables (leaves, grass clippings, etc.) and poor soil that was being dug out from other locations at the same time. It saved on needing to dispose of that waste elsewhere, and on the cost of filling the remaining portion of the beds. Win win!
Your growing soil options depend on what you’ll be planting, and can be a combination of compost, topsoil, garden soil mixes, and/or additives and fertilisers. Topsoil or cheap blends usually lack the nutrients needed for good growing, but most compost on its own is too rich, as can be some ready-made garden mixes for certain plants. You might find yourself wanting to create your own custom blend instead of buying a single source, especially if you’re filling big beds. Our soils were delivered by the dump truck load from a local landscape supplier, and it was quite a wheelbarrow and shovel workout moving them from the driveway to the back garden!
Refreshing Raised Garden Beds for Replanting
Hungry Plants, Hungry Soil
As temporary plantings grow, they deplete the nutrients in the garden bed soil. Enhancement before replanting and/or crop rotation for soil fertility can be used to help maintain your garden’s health and productivity over time. A combination approach is especially handy in cooperative climates, like ours, where it’s possible to cycle through different crops all year round rather than just a single annual growing season during summer.
Soil is best worked when it’s dry or semi-dry. Working wet soil is not only physically harder, it will be more difficult for evenly distribute your amendments and can contribute to soil compaction. Our beds are all fully accessible from the sides without any climbing or stepping, which makes life easier. The big raised veggie beds are also roughly the same height as the lip of a wheelbarrow, which makes it a lot easier to shovel in extra soil, compost, or other amendments without making a mess on the paths.
Clear away any lingering old plants, leaves, or unwanted other garden debris before getting to work. Pull any weeds or volunteer seedlings (save them, if you wish) so that you have clean slate soil to amend. If your garden beds need physical maintenance, like replacing a board or tightening screws, now is a good time to tackle those tasks before you add extra soil, pressure, or weight.
Break Up the Soil
Minimising digging helps preserve the structure of your soil. If necessary, you can lightly fork or turn the upper portion of the soil, removing any unwanted rubble, roots, or other materials as you work. In our veggie beds, with the exception of root vegetables which are harvested in full, I tend to cut the stems of spent or harvested plants off at ground level and leave the roots in the soil until I’m amending or replanting. In most cases, by the time I’m ready to turn the soil they’ve self composted to a point where the remnants stay in the beds as decomposing organic matter along with the compost. It’s better for soil structure and microorganism retention, too. It’s not true no-till gardening, but it’s a middle ground that works for my growing space. Our year-round growing cycle benefits from compromise.
As a soil saving tip, I like to use this opportunity to dump the spent soil from pots and planter bags I use for annuals and veggies, too. The empty raised planters are a perfect opportunity for mixing and refreshing that dirt, too! I dump them out distributed around the top of my garden bed soil (remember to group pot/bed families from a crop rotation perspective, if applicable) and refresh everything all at once, then refill the pots and planter bags before doing a final levelling on the raised garden beds. Perfect!
Add Organic Materials, Fertilisers, and/or Other Amendments
Distribute your other amendments over the surface of your soil. What to use depends on your soil conditions, upcoming planting plans, climate, and personal preferences (e.g. organic vs. chemical). Depending on the bed, I usually take the opportunity to add compost, vermicompost, worm tea, and fertiliser.
Mix to break up any clumps and try to distribute things evenly, noting the comments above about soil structure. Depending on what you’ve added, you might need to lightly fork or turn things, or you might just need to smooth, wet, and let nature blend its self. Once mixed, fill pots (if applicable) and then smooth the surface of the garden beds to a roughly even level. Rake the surface and wet the soil to moisten if/as needed.
Resting Beds Before Planting
Depending on your soil, amendments, and planting plants, you might want to let the soil rest before replanting. I generally like to give things some cooling off time if using commercial compost or rich garden mix. They tend to be very warm on delivery! I also like to let things settle, and preferably cycle through a good hard rainfall before planting so that the surface of the bed can be adjusted and evened if/as needed. I find this particularly helpful when direct sowing seeds for less disturbance. As a bonus, if my mixture is harbouring lingering volunteers or seeds for weeds, there’s a chance to clear them out before they try and sneak in amongst the new plantings, too.