Saturday, March 13, 2021

Gardens and Gardeners are Thawing Out

Robins are making an reluctant appearance and squirrels are active, so it must be Spring. But it’s a slow process in the garden. Spring doesn’t so much begin with warm sunny days; it begins in the dark, deep in the soil as the ground thaws

Sunshine may warm the top few inches of soil, enough for snow drops and crocuses, but the frost recedes more as the residual heat from the earth pushes upwards. Not until the soil reaches an optimal temperature do the roots wake up and begin feeding sap upwards. When the air is warm enough, it continues to flow, buds swell, leaves sprout and spring really arrives. And that will be another week or so.

Gardeners however, have been thawed out for some time and can’t wait to act on their plans and dreams. For many, it will be their first venture into the world of gardening, whether it’s a few containers on a deck, a flower bed, or a raised bed for vegetables.

That concept has taken off, especially among young people eager to grow fresh veggies in the backyard. Depending on soil conditions gardeners have always raised their beds above surrounding soil levels. It’s done to ensure good drainage, or simply because there isn’t sufficient existing soil in the typical backyard. Often there’s only a few inches provided to sustain grass, and not without copious amounts of water and annual fertilizing.

By raising and enclosing the bed it becomes in effect a large planter, suitable for a small backyard where space is at a premium. These are usually built with lumber, although other materials can be used. Cedar, redwood or cypress are good, though pricey choices — it’s a long payback term for a few tomatoes and carrots. Low grade lumber won’t last long before deteriorating but it can be okay if it’s only going to be in use for a limited time.

Pressure treated lumber is no longer treated with arsenic as it used to be, and from what I’ve been able to determine there are no issues with the copper compounds that are currently used,
however, I’d still be inclined to line the wood with polyethylene film. Cement blocks or old logs, though not as tidy, will also do the trick.

The bed can be any length, but a metre and a half wide (four feet) allows for easy access without having to step in. This avoids compacting the soil as everything is within easy reach for planting, weeding, or harvesting. As for depth, a minimum of 20 centimeters (eight inches) is fine, although the bed can be built much higher if the old back is getting creaky.

As for soil, regular top soil can be suitable depending on the source and consistency. Sandy soil drains quickly and has fewer nutrients while clay soil is richer and holds moisture longer, but it’s heavy and compacts easily. Both these soil types are improved by adding organic matter such as manure, compost, or leaves.

A popular alternative is triple mix. There isn’t a standard composition, but it’s typically a friable blend of regular soil, peat moss, and other organic matter. As the organic matter breaks down, the soil will settle and eventually need topping up.

Contained raised beds do tend to dry out faster than a regular bed, so watch for that. Adding mulch will save on water and reduce the need for weeding. One big advantage often touted is that the soil warms up faster in spring, allowing for an earlier start, however, keep in mind that it will cool off just as fast in fall.

Meanwhile gardeners, stay cool, real Spring will soon arrive.

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