Complimentary Blueberry Juice

With the now-one-year-old-hoop-house, we’ve had to pay a lot of attention to water quality. Simple reason being that once you put up a piece of plastic over the ground, it will never again rain naturally on that ground….therefore it is up to us to provide 100% of the water needs of the crop.

This presents a problem when our ground water enters the equation, as our groundwater is absurdly, absurdly hard. There is a mineral crust over anything it touches, it will prevent shower heads from functioning properly and so on, and even the water softener guy keeps adding drops of reagent to the test tube, and more drops and more drops, before proclaiming “holy shit your water is hard.” Yes indeed our TDS (total dissolved solids) is over 1000. In case you don’t speak water hard-ese, that’s enough to make a reverse osmosis expert suggest that before running water through an RO system it goes through the softener first!

So, we have two options. One: collect rainwater. Two: install an RO system.

Last season we did collect rainwater, but in a drought year, this is where the problem with rainwater collection becomes obvious: you can’t collect if it doesn’t rain! So last year we relied heavily on the ground water, which lead to mineral crusty stains all over our greenhouse. I wrote about that and doing a 180 in the hoop house last season.

The good news is that from that first year of hoop house management we also learned how much water we actually needed to run the thing, and it turns out that actual required water was far far far less than we had originally thought. We are not watering every day, or even every second day. With a mulch and covering our soil, we can even be down to once a week. On super hot weeks, maybe every 3 or 4 days. And with drip tape, we are super efficient with that water delivery.

We are used to collecting rainwater, but this year we kicked it into serious mode. We have our initial collection off the shop roof, about 1400 sq ft, that holds 1000L, requiring a light 8 or 9mm of rain to fill. That initial collection can spill over into a 1000L tote, and that tote, can be pumped out to the hoop house into a third tote, for a total of 3000L holding capacity. A single thunderstorm bringing us about 27 mm of rain would translate into all three totes full.

I cannot emphasize enough how super great this is. Rainwater is just different. If you grow plants for long enough, you will know this intuitively. Plants do not respond to ground water or tap water or any other kind of water the way they do to rainwater. Rainwater is of course, full of nature…of micro nutrients, dust, bacteria, algae, in other words, plant food. And plants have, in their genetic programming, evolved to require rain to live. This means there are signal pathways to detect rainwater, and even a light dusting of leaves, some 1mm of rain, will have an effect on plants.

For our uses, it will take about 800L to water the entire hoophouse. From full capacity I would get three solid watering sessions with rainwater.

We can extend that even further by diluting the rainwater a bit with reverse osmosis water, and for that, we have now installed an industrial-sized RO system designed for horticultural purposes, which can process up to 3200L per day of reverse osmosis water, bringing our Total Dissolved Solids from 1000+ down to a mere 0030.

I’m sure our plants and mostly our soil will thank us later.

At least now I’m not worried about continually applying hard ground water to our protected culture plants.

We’ll have a new year of observation and seeing how things go, and what we can do next to improve our watering system even more.

Graham

thanks for reading complimentary blueberry juice

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