There's a lot that can be said about proper soil ph and its effect on the overall health and growth of plants. However, in this article we're not going to go into an in depth study of soil ph itself. We'll take a look at a technique that some gardeners use to change their Hydrangeas from blue to pink by altering the ph of the soil.
Hydrangeas thrive best in acid soil. In acid soils, Aluminum becomes accessible and uptake into the plants increases. The Aluminum is what gives Hydrangeas their blue color.
As soil ph becomes more alkaline, the Aluminum uptake, of course, becomes less. And the more alkaline the soil becomes, the blooms become pink instead of blue.
To make an established Hydrangea turn pink can take a little time and patience.
- The first year sprinkle a half cup of lime around the base of your plants and then mulch to keep it from washing away.
- The next year, dissolve one tablespoon of lime per gallon of water and soak the roots of the plants once a month in March, April, and May.
- If your plants still aren't pink enough, you may have to repeat this procedure another year.
Of course, this procedure works the opposite if you acidify the soil. You can alter or deepen the blue of your Hydrangeas simply by adding a bit of soil sulfur or alum dissolved in water to the soil.
With this or any soil additive procedure it's always best to start with smaller amounts and work your way up. So with making Hydrangeas turn pink be careful and only practice these procedures at your own risk.