Soil Amendments and Wood Ash

Some questions have come in about soil amendments and using wood ash.  I can provide more perspective here, but the topic of soil amendments in particular is huge and ultimately depends on your existing soil’s condition. Do your homework as there is always more of a learning curve.

In Transition Garden, we send soil samples most years off to the Nova Scotia Analytical Testing Lab in order to get a full run down on nutrients, pH and other characteristics.  Alternatively, you can buy soil test kits at most garden centres.  This information is your best guide to understanding how to build your soils.

It is always a good idea to increase the level of organic matter in the soil as much as possible.  Compost, well rotted manures and leaf molds are some of your best sources.  Soils high in organic matter will have a rich soil ecology of microorganisms that will in turn increase a plant’s health.  They also retain moisture better during summer dry spells.  Through the use of tons and tons and tons (literally) of composted manures, we have built Transition Garden soils to a 12-15% organic matter content.  For a gardener, rich soils are literally your main capital asset.

Some of the better and more common organic soil amendments include bone meal, blood meal, seaweed or fish emulsions, green sand and rock dusts.  Investigate each for their levels of N-P-K (nitrogen, phosphorus, potassium) which are the 3 main nutrients required by plants.  They are generally lower in these levels than chemical fertilizers, but are better at building soil ecosystems.

One suggestion that came in:

Leafy greens: need nitrogen

Fruit bearing (like tomato, peppers, potatoes, cucumbers, squash):  need less nitrogen and more phosphorus and potassium

Root veggies: need lots of phosphorus and not much nitrogen

Wood ash is good in soils, but not too much – use sparingly – 10 to 15 pounds per 1,000 square feet.  This is the amount you may get from one cord of firewood.  Also, stir some thoroughly into compost piles.  It adds phosphorous, calcium and reduces soil acidity.

Happy planning, Bob




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