“55g barrel and soaker hose getup to alter city water pH for Blueberries in bulk” or “Is growing blueberries in central Texas insane?”

Our tap water originates from Lady Bird Lake which is a dammed up section of the Colorado River. Central Texas is is full of limestone and it raises the pH of the Colorado quit a bit. I just checked the most recent City of Austin Drinking Water Quality Report (May 2011) to get my facts straight about our tap water and I actually underestimated its alkalinity. I’ve always thought it was 8.5 – 9.0 pH but it averages over 9.5 pH on this report! I really think the alkalinity of the water plays into some of the nutrient problems we see in our garden. That’s a little different story though.

Blueberries like acidic soil around 4.5 pH and can tolerate soil up to 5.5 pH. To create our blueberry bed I dug the soil out of a 20′ x 3′ x 2′ area. I filled it in with some soil I mixed up from peat moss, pine bark, compost, sand, sulfur … and it’s been a long time so I can’t remember the rest of the recipe for certain. The peat should have given us some really nice acidic soil as it’s around 4.5 pH. Add in the sulfur and pine bark and we should be golden, right?

Well, before using the peat you have to soak it really well to hydrate it. The only way for me to do that was with our 9.5 pH city water. We planted the blueberries and hoped for the best. The blueberries got planted in the winter. Six months later they had leaves, but weren’t growing much and frankly looked horrible. I finally stuck a pH meter into the dirt and… arg… 7.5 pH. Blueberries don’t like it. I guess the limestone from the city water was raising our blueberry bed’s pH. Fiddlesticks. I thought between the peat, sulfur and pine bark it would counteract the city water. I thought wrong.

To correct the problem I watered (and watered and watered) with acidic water. I’d mix 1 cup of vinegar into 2 gallons of water to get the pH down near 4.5 and then I’d pour it on the blueberry bed. I went through many gallons of vinegar, 1 cup at a time in a 2 gallon watering can. It took a long time. I finally got the pH of the blueberry bed to read around 5.5 pH, but how was I going to water my blueberries from now on? Mixing up 2 gallon batches to water a 20′ x 3′ area is for the birds.

Well I saw a post on the permaculture subreddit about using a 5 gallon bucket and gravity to irrigation. Brilliant! It gave me the idea for an easy way to water my blueberry bed. I’ve got a 55 gallon barrel on the porch. Fill it with water, pour in at least a gallon of 9% vinegar, use the hose to create a siphon (it’s up on the porch, about 1′ higher then the blueberry bed) and then simply attach the hose to the soaker laying on the blueberry bed. I was worried there wouldn’t be enough pressure to force the water out of the soaker evenly but that doesn’t seem to be a problem at all. It does take all night for the barrel to empty but I think that’s probably the best way to water.

It’s a month later now, the blueberries are putting on some new leaves and look healthier. But, I still have a few questions about watering our blueberries, pH, acidity, and all that nonsense:

If my soil is 5.o pH and I use water that’s 6.0 pH is that going to raise the pH of my soil?

Rainwater is ~7.0 pH, will that raise the pH of my soil?

When I pour the vinegar into the 50 gallon barrel to drop the pH I assume it’s dissolving the limestone. What does it turn into? Is it some sort of salt? Oi.. I think that would be bad for the berries as well.

Is this insane?

Anything I’m missing?