Why solarpunk?

Solarpunk has many aspects, including technology. We want to use refreshingly simple tech solutions to make our lives better.

Sure, you could just use a dripping line, plug it into the hose, and add a watering computer/ timer/ smart home. That’s what many commercial solutions offer.

But it also has its disadvantages.

• Dependence on water and electricity grid. You often don’t have that conveniently nearby, or even at all in many cases.
• You have to use tap water. In many places, it includes very harmful stuff for plants (chlorine, etc.), and in most places moderately harmful stuff (alkaline minerals, causing nutrient lockout). You also can’t use collected rain water.
• More expensive and less modular. Can break.
• No moisture metering. It just blindly pumps water into the dirt, resulting in too much or not enough irrigation.

The methods I show you now are low-tech and “just work”, even off-grid!

Why automatic irrigation?

“Why even start automatic irrigation in the first place? What are the pros?”

Using the watering can or garden hose is intuitive and quick. At first. But if you have to water a lot, it adds up. In summer, you often have to water twice a day, and that can be backbreaking work if you have to do it in a greenhouse for example with lots of thirsty plants.

Automatic watering also saves you lots of water. You’ll only need 1/3 compared to surface watering. That’s especially handy if you have limited access to collected rain water. Regular watering is more wasteful, because the surface moisture doesn’t add much value and evaporates quickly. Automatic irrigation on the other hand gives it directly to the roots where it’s needed the most. The surface stays relatively dry.

This also makes the life of weeds harder. They can’t sprout or grow much when the surroundings are dry.

And, it can reduce pests like fungal infections, because the leaves don’t get wet and no spores are released into the air. Tomatoes and melons for example benefit from this.

Now, that you’re hopefully convinced, let’s see what options we have :)

Oyas and other terracotta stuff

Oyas have already been around for thousands of years. It’s a pot made out of unglazed terracotta that gets buried in the ground. You fill it up with water, and it gets drawn out slowly by surrounding soil.

The drawing action is dependent on surrounding moisture. If the soil is dry as heck, the oya will be sucked out in days. If it’s moist enough, it can last over a week sometimes.

A “modern” version of this are cones with wine bottles.

Sadly, the terracotta is not frost resistant and will break in winter if you don’t dig it up again before.

The moisture radius is also quite small, particularly the bottle cones.

But especially in pots this works very well!

Wicks

Include a wick (polyester) into the pot and suspend it above water. It will draw it up and supply the substrate with the correct moisture.

Blumat dripper

The moisture isn’t released by the cone itself. It only checks the surrounding soil moisture. When the substrate dries up, the internal pressure changes and a valve opens, the tube starts dripping. As soon as the surroundings are moist enough, it closes again.

You connect it to a water tank suspended slightly above the soil line, and physics does the job.

The main advantage is that there’s no cap on how much water it can release. This makes it ideal for open setups without containers, like a greenhouse or bushes.

Going fully hydro

The above solutions are mainly meant for gardening soil (or similar substrates).

But what, if you don’t even need soil? Let’s go fucking hydroponic!

As I try to teach in !hydroponics@slrpnk.net, hydro doesn’t need to be complicated. It can be as simple, passive and robust as you want!

Here I use old glass bottles to grow lettuce and basil Kratky style:

I already made a post about that topic.

I don’t need to refill it up to the first 2 months, and after that, about weekly or so.

I also have many plants in coco coir, which is also a hydroponic medium. It can store absurd amounts of nutrient solution, and thanks to the added perlite I can’t get root rot. I only need to water it every few days, using bottom watering. Quick and simple.

I also love “Semi-Hydro”, where I use LECA (expaned clay pebbles) as a substrate, which is partially submerged in nutrient solution. The moisture is drawn up via capillary action, resulting in a perfect mix of ideal moisture and extreme aeration. I use it on my ~100 houseplants and a few other ones.

And, last but not least, my solar dripper.

Based on Semi-Hydro, it holds 40 l LECA, 15 l reservoir, and a small cheap pump powered by a solar panel, recirculating the nutrient solution.

This creates an environment only comparable to aeroponics, but more simple and robust, proven successful by years of harsh outdoor conditions.

The growth and vigor is just insane!