Why We Should Lime

Spring garden

Here on the wet West Coast we get rain.  I’m sure you know that already but how does a lot of rain make our gardens different from those in Kamloops,Vernon or in other parts of the country?  Besides helping the plants and grass grow lush and green, lots of rain has a tendency to make soil acidic which is why rhododendrons and azaleas do so well here.

Coniferous trees also add to the acidity of the soil in our garden.  Years of needle drop can be a nightmare for the gardener who wants to under plant their mature trees with pretty spring flowers.   Plants just can’t get their roots on nutrients in a soil that is too acidic.  Some diseases like club root in brassicas can be attributed to insufficient levels of lime in the soil.   Also, if you have clay soil, well, it’s naturally acidic.

So, what is a gardener to do?  Don’t throw up your trowel in despair as there is a fairly simple solution to this problem.  Lime.

You’ve probably heard of liming your lawn.  Using lime in the garden is really no different. The objective to both is to sweeten the soil to make nutrients more available to the plants whether it’s grass or geraniums.  Usually you lime your lawn a couple of weeks before applying fertilizer so that the fertilizer can be taken in by the roots more readily.  Same in the garden.

Now this doesn’t mean you should start spreading lime about willy nilly.  First you should test your soil to determine what areas are acidic and what are alkaline.  For about $10 you can get a basic soil testing kit from the garden centre (that would be Cultivate Garden & Gift).  This test will tell you the Ph level of your soil and help determine if it needs an application of lime to make it more alkaline.

“Apply dolomitic lime as needed to maintain the soil Ph between 6.5 and 7.0. This is necessary to make soil nutrients available to plants” so says the Ministry of Environment.

While dolomite lime is okay it breaks down very slowly, taking months to actually work.  This is the stuff that blows about when you spread it, making it look like you’ve dusted everything with icing sugar.  Dolopril is a better way to go as it is a pelletized lime, lighter in weight, covers a larger area, is much easier to spread and doesn’t have that icing sugar affect.  Plus you’re less likely to breathe any in as it’s not so dusty.  On top of all that it breaks down much faster than other limes, doing the job in a few weeks.

Liming should be done in the early spring (like now) to have the most benefit.  Some plants, such as lilacs & spiraea, like a sweet soil (alkaline) but you should be mindful not to apply lime around rhodos, azaleas, camellias, heathers and other plants that typically love acidic soil (moist, woodland type plants).  Lime can also be used in the vegetable garden but spuds don’t particularly like sweet soil so avoid that bed.   And of course, you can apply lime to the lawn anytime now, preferably a few weeks before you apply fertilizer.

So, while our neighbours in East are still shivering or shoveling we can enjoy the odd sunny day between showers and be out in our garden.  Liming is a small price to pay for being able to garden pretty much year round.

Shirley Eppler

February 2012