Return to the Soil Forum | Post a Follow-Up

 o
Determine soil pH organically

Posted by ceth_k 11 (My Page) on
Tue, Jan 15, 13 at 22:11

Is it true that Hydrangea's flower become blue in acidic soil and pink in alkaline soil? If it is true, then maybe this flower can be used for determining soil pH easily?


Follow-Up Postings:

 o
RE: Determine soil pH organically

I believe that hydrangeas have that quality, but how does that help vegetable growers? Also determining the degree of acidity and alkalinity might not be known very well.


 o
RE: Determine soil pH organically

I guess that is true but it is usually a good idea to send out a sample to find out everything else anyway. I pay about 8 bucks per sample to test for the usual stuff,P,K, Mag, cal,ph.


 o
RE: Determine soil pH organically

It's true, but breeding is stretching the expression of the colors in some modern Hydrangeas so people in high/low pH gardening areas can more easily get the color they want.

It's still neat, though not ideal as a pH indicator besides a basic understanding of what may be going on in your neighborhood/yard based on how they're growing.


 o
RE: Determine soil pH organically

Some Hydrangas, macrophyllas, will blossom blue in an acid soil and pink in an alkaline soil but not all. Some of those that did express that trait have also been bred to not do that.


 o
RE: Determine soil pH organically

Someone needs to breed a very accurate one that changes colors every 0.5 pH units. They could call it Litmus Hydrangea.


 o
RE: Determine soil pH organically

Or Phydrangea.


 o
RE: Determine soil pH organically

Fwiw, the expression is tied to aluminum availability. At low pH aluminum is abundant for plant uptake and it leads to the "blue" expression. At high pH, Al is generally tied up/unexchangable in soil and leads to the "pink" expression.

Technically you could saturate a high pH soil with high levels of aluminum and get a blue (or blue-ish) expression even though the pH is still high. That said, this would be a very rare thing to find in a natural soil and would be a result of pollution. Also, fwiw, once this plant available aluminum in the soil is "used up" the new flowers would flush pink and some of the older flowers may revert to pink.

Aluminum and pH influence is neat...especially for a highly toxic plant (and human) metal.


 o
RE: Determine soil pH organically

also, lol Phydrangea


 o
RE: Determine soil pH organically

Perhaps pHydrangea then. :-D

Thanks nc, I have one and did not know it was related to aluminum availability.


 o Post a Follow-Up

Please Note: Only registered members are able to post messages to this forum.

    If you are a member, please log in.

    If you aren't yet a member, join now!


Return to the Soil Forum

Information about Posting

  • You must be logged in to post a message. Once you are logged in, a posting window will appear at the bottom of the messages. If you are not a member, please register for an account.
  • Posting is a two-step process. Once you have composed your message, you will be taken to the preview page. You will then have a chance to review your post, make changes and upload photos.
  • After posting your message, you may need to refresh the forum page in order to see it.
  • Before posting copyrighted material, please read about Copyright and Fair Use.
  • We have a strict no-advertising policy!
  • If you would like to practice posting or uploading photos, please visit our Test forum.
  • If you need assistance, please Contact Us and we will be happy to help.


Learn more about in-text links on this page here