Gypsum? What’s that? Why do we use it?

Seems like farming would be a piece of cake, right? Just plant some seeds in the ground, twiddle our fingers, and wait for the veggies to emerge? Well, there’s a LOT more to it, and believe it or not, it includes chemistry, too! Our use of soil amendments generated lots of interest at the CSA Potluck and Slow Food Austin Farm Tour this past weekend, spurred by the piles of colorless mineral located intermittently around the farm. So slide on your science goggles, folks, and get ready to learn a quick thing or two about this mysterious mineral, gypsum! Steve Diver, an agri-horticultural consultant superstar who has been working alongside us since we made the leap from the Hergotz farm to the 200 acres in Garfield, took some time to chat with us this week and divulge his breadth of horticultural knowledge on the subject.

Gypsum! Photo by Scott David Gordon.

Soils in central Texas are derived from limestone geology, which means they are calcareous (or high in calcium), and are highly alkaline with a pH over 7.5. Therefore, you normally wouldn't add extra calcium, such as agricultural limestone, to these soils. However, a confounding factor is that the irrigation water we use contains a lot of sodium and bicarbonate which upsets the balance of exchangeable cations like calcium, magnesium, potassium, and sodium. This affects nutrient availability to our vegetable crops. Thus, gypsum, or calcium sulfate, is the perfect soil amendment to address this particular issue. It adds calcium to offset sodium without increasing the soil pH. That's why we take soil tests and add a suite of compost, organic fertilizers, and minerals to our fields every year -- to make sure our crops are well fed and taste good. ***

Gypsum. Photo by Scott David Gordon.

Interesting, eh? On top of the aforementioned facts, gypsum is known to improve water filtration, augment soil structure, reduce nutrient runoff, aid in reducing erosion, and improves plant nutrition overall so you can enjoy the most tasty and nutrient-dense vegetables! Whoda thunk? Farming and chemistry go hand in hand sometimes, are you surprised?

Gypsum at work. Photo by Scott David Gordon.

A big thanks to everyone who joined the fun at the CSA Members Potluck and Slow Food Austin Farm Tour this past weekend, especially to our CSA members and Slow Food Austin. Not to mention the delightful fermented beverages from the powerhouse trio of local brew-masters, Jester King, Hops and Grain, and Adelbert’s on Saturday night, and the mouth-watering culinary curation from Snooze Eatery on Sunday morning. We are grateful for everyone’s time and contributions. We had a blast and hope you did, too. Find more photos from the event here!

Potluck night! Photo by Scott David Gordon.

Potluck deliciousness. Photo by Scott David Gordon.

Potluck noms. Photo by Scott David Gordon.

Potluck farm tour. Photo by Scott David Gordon.

Potluck peeps. Photo by Scott David Gordon.

“I just wanted to take a second and thank you sincerely for such a wonderful night. We had a great time on Saturday. My only regret is not having joined the CSA months sooner. Every Tuesday afternoon, Sammy and I sit together on the porch waiting for our delivery. I loved being able to show him where our veggies come from. Brent, you've creating something beautiful and powerful and I'm grateful to share in that and teach my kids about it.” -CSA Member 

Get spooky with us and join the fun at the HOPE Night market this Friday! It’s from 6-10 pm at Plaza Saltillo. Find more info here.

Are you an Austin Energy client? If so, you are eligible to receive a free tree at the Sunset Valley Farmers Market this Saturday! Bring your ID, grab a tree, and visit Matt Pelkey at our stand for some veggie goodness! Check out the event here.

***major contributions by Steve Diver