pH Preferences of Plants

pH Test Kits

Simple soil test kits are available from most garden stores. These kits usually allow you to take pH readings from several areas.... my last kit from CIL had 4 separate test vials for measuring pH. Thus with one kit you could measure the pH from your vegetable garden, front lawn, flower bed and under the hedge. Results are ready within minutes, by comparing the colour your vial has turned, to a colour chart that comes with the kit. You can usually guess at the colour to within .5 on the pH scale. For example, my last kit came with colour bars for pH values of 5.0, 6.0, 7.0 & 8.0. My vial was definately in between the 6.0 and 7.0 for my lawn, so I say the pH is 6.5. (best guess). Most plants have a wide range of pH values they like and being within 0.5 on the pH range is fine.

pH Preference of Fruits and Vegetables

pH Preference of Flowers,Trees,Shrubs and Annuals

pH Preference of Turf Grasses

Adjusting the pH Level Of Your Soil

You have the choice of picking plants that like the existing pH level of your soil, or you can adjust the existing level. Most plants have a reasonably wide tolerance and can stand pH levels that are out by 1.0 points. Adjusting the pH level is not an exact science and takes time. Work slowly towards the ideal pH level.

You can correct the pH level at any time of the year, but it is best to start in the Fall and check progress in the Spring. Wait 30 days after an adjustment before retesting.

Soil Types

Sandy, Loam and Clay soils will use different quantities of material to make a similar sized pH adjustment.

Sandy Soil - a light, course soil comprised of sand and ground rock debris.

Loam Soil - a medium crumbly soil, consisting of a blend of sand and clay particles mixed with humus (organic matter).

Clay Soil - a heavy, clinging, impermeable soil, comprised of very fine particles with liitle lime and humas and tending to be waterlogged in winter and very dry in summer.

Adjusting Soil pH

Ensure the treated area receives 2.5 cm (1 inch) of water, either from rain or a sprinkler, within 7 days of application. This will activate the corrective treatment.

Amounts listed are in kg per 10 sq meters.

* - Do not add more than 2.5 kg/10 sq m. of lime in one application. If more lime is required a second application can be made in two weeks. Allow 30 days before testing again.

Allow 30 days after adding lime or sulfate before adding fertilizer.