Liming The Garden

My daughter Jasmine was recently at Bushy Park just out of Wanganui with her biology class studying the ecology of the local bush there. It was a wet day and large drops of rain were filtering through to the undergrowth from the taller trees above .Jasmine   was amazed to notice that the droplets were in shades of green and blue. Her tutor informed her that she was witnessing acid rain. But not a detrimental kind. This acid rain was formed from lime spread over the local pastures. Rain and humid weather had melted the lime and much of it   had been absorbed into the atmosphere where it accumulated in clouds and then released as rain .A very beneficial kind with a perfect p.H for the native plants.

Lime is such an important element for plants growth. It’s not so much what it does for the plants but what it does in the soil to allow plants to grow well. When we fertilise our plants ,either with organic or artificial fertilizers the elements in them are released as ions in the soil .In highly acid and alkaline soils these ions become locked up so that the plants cannot use the fertilizer. This is the main reason plants don’t grow well.

Simplistically we talk about soils being  either acid or alkaline. Here on the coast our soils are naturally acid. An easy indicator of soil acidity without having to buy a p.H meter is to look at Hydrangea flower colours. Most are blue in our region or mauve blue. And white flowered varieties have blue eyes. In alkaline or “sweeter” soils the Hydrangea flowers would be pink or red and white flowers have red eyes. The addition of   Lime is the usual element that  reduces the acidity of the soil to allow the fertilizer to become readily available to the plants. In other words lime your ground and your plants will grow stronger and healthier. The closer you get your soil acidity to neutral, which is measured on a p.H scale as 7.0, the more nutrients that will become available for your plants to use.



Farmers have always known this and regulary lime their fields and there has always been a tradition of liming vegetable gardens. But few gardeners seem to extend this liming to the rest of their gardens. I believe its because of our anglo saxon roots. In England much of the soil type is limestone which is alkaline and gardeners have to go to great lengths to acidify their soils. Lime is a poison and much is written in gardening books about not liming acid loving plants such as Camellias ,Azaleas and Rhododendrons. I have used lime liberally for many years   all over my garden, including the fore mentioned plants with no ill effects.

The veggie garden I lime twice a year when the crops are changing into winter and summer mode. The rest of the garden gets an annual dose sometime between autumn and winter. I wait until the garden has had its big clear out and the ground is clean. Lime doesn’t burn and can be safely thrown over foliage   but I still prefer to lime when I know rain is imminent so it gets washed in quickly. Never mix lime and other fertilizers as a chemical reaction will cause nitrogen to be released into the atmosphere and lost. I like to wait at least three weeks before the separate applications.

Lime is   relatively cheap compared to other fertilizers and can be purchased by the trailer load or tonne   from bulk suppliers if your garden is large. Bagged lime is readily available from all garden shops. Be prepared to use some muscles as even small bags of lime are deceptively heavy. Dolomite lime is another form of lime offered for sale. It has the addition of magnesium sulphate or Epsom salts but makes this lime quite expensive compared to the plain lime.

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