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. This is usually done when the garden cycles through removal of spent plants and prep for replanting with new seeds or seedlings. They’re the main 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 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
Saving When Starting a New Raised Garden
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!
Raised Garden Bed Soil Options
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 far 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. Bulk buying might also help. 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 Bed Soil for Replanting
Hungry Plants, Hungry Soil
As plants 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 Conditions
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.
Clean Start
Clear away any lingering old plants, leaves, or unwanted other garden debris before getting to work on the soil below. Pull any weeds or volunteer seedlings (you can save them, if you want to try replanting) so that you have clean slate soil to amend. If your garden beds need any 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, I often 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 many 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 sometimes use this opportunity to dump the spent soil from annual pots and planter bags. The empty raised planters are a perfect opportunity for mixing and refreshing that dirt. I dump and spread the soil out around the top of my garden bed soil (remember to group pot/bed families from a crop rotation perspective, if applicable), refresh everything all at once, then refill the pots and planter bags before doing a final levelling on the raised garden beds. Easy as! Alternatively, I can in the holding bay of our composter as long as there are no crop rotation issues to consider.
Add Organic Materials, Fertilisers, and/or Other Amendments
Distribute your amendments over the soil surface. What to use depends on your soil conditions, how hungry a feeder the last crop cycle was, your upcoming planting plans, season/climate, and personal preferences (e.g. organic vs. chemical).
Depending on the bed and the rotation, I like to use the opportunity to add compost, vermicompost, worm tea, and/or fertiliser to help refresh our soil.
Once amended, mix 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. Or you might just need to smooth out the surface, wet the soil, and let nature blend its self. In either case, once your soil has been mixed, you can use any excess to fill pots (if applicable), and then smooth the surface of the garden beds back to a roughly even level. Rake the surface lightly and then 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.
