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Ph level

PostPosted: Mar 17, 2010 11:58 am
by BackerBunch
What is the best ph level for hostas? When I Googled it, one place said between 5.5 & 6.5. Another place said between 6.5 & 7.5. Does it depend on the type of hosta? Or it's color?

Re: Ph level

PostPosted: Mar 17, 2010 4:00 pm
by Chris_W
Hi Brenda,

Most hostas are fairly tolerant of different pH levels, so long as it isn't too high. If the pH gets too high (higher than 8) then many of the nutrients in the soil become insoluble in water, meaning that the plants simply can't draw up nutrients into their roots after it rains. Some plants make do with what they get, but others won't tolerate those conditions.

It is best to have slightly acidic conditions (under 7.0), but most plants won't be affected by a pH a little over 7 (slightly alkaline conditions).

If you ever hear that a hosta needs "lots of water" to perform well, this could really be a plant with an eating disorder that doesn't feed well. Tattoo and Great Expectations come to mind as plants that need to constantly feed and do not tolerate high pH conditions. Many of the really big plants are like this too, like Mr. Big.

Tattoo is related to Little Aurora and I think that whole family of plants, Little Aurora, Tattoo, Little Sunspot, and Sultana, needs to have a low pH level to do well. Those plants all grew really well for me at our old place where we had dry conditions but low pH. When we moved here where the pH is very high but ironically the soil is fairly wet, that group of plants actually dwindled away.

We work Hollytone fertilizer and lots of compost into our soil when we plant. The compost we get from the city of Ann Arbor has a pH that is almost neutral, however it is low in sulfur, which the Hollytone has added to it. Sulfur gets eaten by soil bacteria, turning it into Sulfuric Acid which in turn lowers the pH. It is a slow process, but in time our pH is coming down here, and the hostas are all starting to grow bigger, faster.

Hope that helps :)


Re: Ph level

PostPosted: Mar 17, 2010 6:48 pm
by BackerBunch
Thank you, Chris! That actually helped a lot. We live on a hill that is nothing but red dirt but we've bought some compost from the city of Charlotte for a couple of years to work in our beds. We've had a very wet winter so I'm curious how that's going to affect my hostas. It might also explain why they haven't done as well in the past. In the past several years we've had a drought. To compensate, I overwatered. (Yeah, I'm in dire need of some hosta education.) My soil tester has been misplaced so I have no idea what our ph is right now but I'll be getting another one tomorrow. Thanks again!