That study about soil pH changing flower colors surprised me more than I expected

I was reading this blog post from the University of Vermont extension service last week, and they had a chart showing how hydrangea blooms shift from blue to pink just by adjusting soil pH from 5.5 to 6.5. I always assumed it was a specific fertilizer you had to buy, not just a simple pH change. They even gave a timeline: it takes about 3 to 4 months to see the color shift after you amend the soil with aluminum sulfate or lime. That blew my mind because I've been buying expensive color-changing products for years without knowing the real cause. Anyone else find out a simple science fact that made a bunch of your past gardening efforts feel unnecessary?

2 comments

2 Comments

lopez.brooke17d ago

I get where you're coming from, but I gotta push back a little on the "expensive products were unnecessary" part. Sure, the pH thing is the real science behind it, but those color-changing fertilizers aren't completely worthless. They usually have the aluminum or sulfur already mixed in with the right nutrients, so they make it way easier for people like me who don't want to mess around with measuring soil pH and adding separate stuff. I tried the plain aluminum sulfate route once and ended up burning my hydrangea roots because I put too much in too fast. A few bucks for a product that already has the dosage figured out saved me from killing a plant I'd had for years. Sometimes the shortcut products are worth it just for the peace of mind and the fact that they do work, even if you now know the simple science behind it.

miles27717d ago

I bought one of those all-in-one blueberry fertilizers last spring that has the acidifier already mixed in... it cost like $15 for a bag but I didn't have to guess at anything. @lopez.brooke you're right about the peace of mind thing because I tried straight sulfur on a new blueberry bush once and it took forever to kick in and I never knew if I was using enough. The prepackaged stuff might cost more but when you factor in the cost of replacing a dead plant, it's kind of a no-brainer for me. I still keep a soil pH meter around for checking, but for regular feeding I just grab the easy stuff now.