Building Garden Beds | March 16th, 2020
I feel like it was just the other day that I was worrying about freezing temperatures and here we are picking overwintered cauliflower and lettuce--spring is unfolding quickly!
While some nights are still pretty cold, you can try early peas, potatoes, lettuce, spinach and other annual greens outdoors. In the warmer and more protected gardens they should be fine, but colder, more exposed gardens and gardens in valleys that get frost every morning, wait for a couple of weeks until it is warmer. Given the large number of seedling predators (birds, mice, cutworms, slugs, pillbugs) around in early spring, use plenty of seed if you are sowing directly in the soil to allow for losses. Also, cover plants and seedbeds with floating row cover, plastic tunnels, cold frames or other cloches to keep plants warmer. Such covers also help keep birds and mice out of seedbeds, but don’t have much effect on those other pests I listed, which are often already present in the top layer of soil or leaf litter. The cutworm menace will stop in late April/early May when the caterpillars pupate to become moths, but protection will still be necessary from birds (e.g., cover with plastic or wire netting) and slugs (iron/ferric phosphate slug baits work very well).
Dig your carrots: The end of March it usually a good time to harvest all of the rest of your carrots, beets and other root crops before they starting to grow again. I try to delay harvest day by piling lots of leaf mulch on the last carrots in the garden to insulate them from the warming spring weather, but usually can’t hold them much past early April. As the soil warms, the plants will be intent on developing flowering stalks for seeds, which uses up the sugars stored in their roots. As they grow, the roots lose flavour and produce a lot of weird little side roots. Carrots, beets, etc. keep at for at least a month in the refrigerator after harvest.
Do you need raised garden beds? Although the ‘go-to’ design that we see widely is a raised bed, usually with board sides, this is not the only way to have a garden. Permanent beds, with pathways in the same place every year are desirable for many reasons, but whether beds have to be raised or not depends on location (and personal preference). Raised beds are necessary where there is poor drainage and water doesn’t drain away after heavy rainfall. The raised soil ensures the roots of vegetables don’t sit in water too long after rain stops. Building beds with sides to hold in imported soil is also necessary for people without any soil, who are gardening on rock, patios, gravel areas, etc. However, where you might be converting a typical lawn or yard area to a vegetable garden, it is often not necessary to buy more soil or to invest in building sides to the beds. If you dig down with a shovel and have a foot or more of soil (even if it doesn’t look dark, like top soil) you may be better off spending your money on good compost, organic fertilizer and other amendments for the soil you have, rather than on importing soil or on building sides to the beds. The big problem that arises with purchased garden “soil” (mixes don’t always have soil in them) is that they are not usually fertile enough to grow vegetables to start with. They are a good texture as a starting mix, but you will need to add a generous supply of good compost to the new soil as well as balanced organic fertilizers, at least for the first few years as you build up fertility. The new soil may also require lime to make it less acidic (raise the pH), so always ask the supplier whether they have added lime or not.
If you decide you want raised beds, you don’t necessarily need sides on the beds—again this depends on the site and your personal preference. Because you will never (I do mean never!) walk on the bed, you can pile soil up about 15 cm/6 inches deep and it will stay in place quite well. To build such beds you can just shovel top soil from the pathway onto the bed, thus avoiding having to buy more soil. Of course, you can add purchased soil to build up the depth as well. Besides saving money, a benefit of not having sides on beds is that it is easier to build lovely curving beds…and in my garden, it has allowed me to make the paths narrower every year as I expand the width of each bed (it is rather a glorious jungle by August, but at least there isn’t any wasted space!)
Starting from sod? If you want to have a garden, but are looking at a lawn right now, you will need to kill the sod first. The very best soil you have is in the roots of that sod so stripping it off and getting rid of it is a terrible waste of topsoil and organic matter (all those roots of grasses and weeds are a valuable organic matter source). If you started last fall or mid-winter, smothering sod with opaque covers, you will be all set to add compost and other amendments in another month or two with no need to remove the sod. But if you are starting now, the options are harder: If you can do it right now, go out and lift the sod up and turn it upside down in the same place, with the roots in the air. Leave it for a month or as long as possible, which will dry the sod and kill the roots. When the soil is dry you can shake most of the soil off, on the spot, right where it should be. When I do this I really bang the dry sods hard against a shovel blade until there is virtually no soil left on the roots, then I use the dead grass and roots as a surface mulch. Alternatively, a [poor] second option is to take the sod away to a pile where it eventually dies, then trundle it all back to the garden later so as not to lose your best soil. A third option is to rent a rototiller and chop the whole thing up after the soil is dry enough to handle. This kind of cultivation is very hard on soil structure and on soil organisms (think chopped earthworms…), but it gets the job done fast and the top soil and organic matter in the sod stay in the garden. If you go this route, plan to turn in as much compost, leaf mould or other additional organic matter as you can at the same time, along with a complete organic fertilizer and lime. Spread these amendments on top of the sod before tilling and try to get the job done with the minimum number of passes back and forth with the tiller to minimize the damage to the soil. Just do this once and then plan to never, ever do it again and let the soil community and soil structure heal.