How to integrate rainwater with Greenhouse.

So i am wondering how folks do this.
We have a small green house which has 3- 12' long beds which are about 3 feet in width. We grow a few items like tomato, sweet potato, and new this year is ginger among other veggies.

It however is extremely dry inside the greenhouse. The air will be humid, however the soil itself is dry dry. I would like to incorporate the rain water into the soil so it is less of a demand on me and my sweety. Sometimes we could be watering twice a day.
How can we have a system which waters the greenhouse without our input?

I imagine some sort of gutter leading to a barrel which than slowly, thru small hoses waters the soil. I am wanting to be able to water more than just the garden beds however.


Is anyone doing this? Does anyone have any awesome example(s)?! Maybe a photo?

Please respond :)

It really can be as simple as you said.

BUT.....

There is a LOT more water coming off a roof than most people expect.  If you are going to store it like a rain barrel, you need something a lot bigger than a barrel.  Like several ibc totes.  And that little pressure from gravity is not enough to make drip irrigation reliably even, so care and adjustments may be needed.

It can be as simple as sitting your rainwater in our next to the greenhouse, elevating it above the ground level, and letting gravity feed it through a dripper system - other than the on/off spigot, there need be no moving parts, and no energy consumption to "run".

I've been thinking about this for my own greenhouse.
The gutter gives me pause,  I don't want occlude the sun with a long opaque object.
The tempature of the rain is also an issue to me.
Although it will obviously be above freezing itigjt actually lower the ambient temperature in the green house.
As far as storsge,  I think I would favor daisy chained water heater tanks.
Removing the insulation is optional but it does allow them to be used for solar gain.
Back steel tanks gets quite hot in the sun,  and they have  a small foot print of around 16" diameter.
Or they could be dug into the pathways.


Maybe feed a small header tank, from a sump,  using an solar powered airlift pump .
There are some DIY hacks that let you water a tree over the course of days utilizing a dripper valve, hose, and a 5 gallon  bucket.
Adapting this to water  rows of plants seems doable.

Perhaps an olla system could work for you. The video below shows a nice set-up and I find he is very good at explaining the whole thing. The first 6 minutes shows how he makes the ollas, and the rest shows how he set them in the ground and has them connected to a rain barrel system.
I used ollas over the last couple of summers that I also made myself like the person in the video, and they work wonderfully. I don't have mine connected to the tubing and rain barrel, rather I hand watered them, but the need for watering was so much less than when I didn't have the ollas. It's amazing how the plants' roots grow near to the ollas and take water as needed. I'm planning to eventually make the kind of set-up he has. I already have IBC totes collecting water, and the ollas, of course, now I just need to set up the connections. What's so nice about the whole thing is that it is self-watering. As long as there is enough water in the rain barrels, the ollas will be fed water as needed.

My greenhouse has integrated gutters in the extruded aluminium channels, so it was easy to hook up a barrel system using 200 l plastic drums. There's a primary collector on blocks next to the structure, and the outlet from that goes into the greenhouse, which has an excavated floor. Inside there are three more barrels daisy-chained together to act as a single tank, The gravity feed from the outside barrel is attached to a float valve on one of the inside barrels. All the inside ones are black to maximise heat gain (but since they're back in a corner and covered with plants it's not like they're bathing in solar rays). I also manually fill a bathtub with water from this system, so all together it's about 1000 l of storage and it's quick to do a round of watering when we're dipping the can or bucket out of the bathtub.

So far, in three years of operation, we have not needed to use town water in there once. Everything we've needed has come from the sky. The other thing I've done was to put most of the plants on tables covered with corrugated roofing iron on a slight angle which drains into buckets. This lets us reuse as much water as possible. Can you tell I spent most of my life in a desert?

I'm also a fan of not allowing the humidity to get too high in greenhouses, as that's how lots of pathogens get the advantage. Capturing the runoff helps us control moisture levels.

Hi Jordan, you may be any to consider adding a wicking bed for crops needing watered more often.

Perhaps utilizing grow trays for seedlings. Then the water could be filled and flushed from the trays. Gravity fed would be simpler than attempting to run gravity rain water through a drip irrigation system.

Even though we clean our gutters, have screens at the inflow of the barrels. Our barrels still have some sediment and leaf debris. This debris would clog drip emitters and valves.

Utilizing irrigation parts for gray will have bigger emitters and may work for your set up.

There are many good suggestions listed above. The olla sound really neat-o.

Thank you for all the replies and suggestions everyone. I was hoping the answers would be broader than just my situation. One reason why i would like this to happen is because i have noticed how hard it is to water soil which is dry on the surface. the water tends to pool together and run off in a stream. So i was thinking if it was watered more regularly, thus keeping the surface slightly damp. Thus slightly damp soil would mean that the soil would more readily take a deeper watering.

maybe ollas would work, however it might work better with tomatos and not so much with sweet potatos who vine all over the place.



In a perfect world. I would get the benefits of it raining onto the soil. And i would also get the benefits of it being warmer/hotter. I am realizing this might not be achievable. Our tomato plants would not really like the added water on their foliage. The thing i am wanting to increase is the soil activity. With it being almost desert like, paths are super dry, garden beds are super dry. how can i make it so the whole space is biologically active. I would love it if i dug a little bit into the soil and saw that it was moist. Recently i pulled a ginger plant out of the ground and boy was it dry all around the plant!


Right now it seems i can only water deeply wherever i water. And with the garden beds being somewhat raised, this means some of the water runs off of them and gets the path way all wet. I am wanting to change this. I would like the whole area to get drenched at least once a month.  Maybe somehow in the winter i can drench the area? Or maybe i can run a sprinkler in the greenhouse for 3 hours in the summer/spring. Along with using compost teas.

Does anyone have any thoughts?

jordan barton wrote:Right now it seems i can only water deeply wherever i water. And with the garden beds being somewhat raised, this means some of the water runs off of them and gets the path way all wet. I am wanting to change this.

Have you considered swale beds? This is what I'm doing in my garden and after reading your thread, should consider doing in our future greenhouse. I dig my beds about two shovelfuls deep and fill with chunks of logs, branches, soil, woodchips, and compost like hugelkultur. The water gets trapped in the swale and I find these beds are easy to water and retain moisture for a long time. Of course, since you're working with an established greenhouse, digging the current beds out may be more trouble than it's worth.

I live in the desert and my soil is sometimes hydrophobic like yours. I use two methods together, one of which is traditional in my region and one of which is from the US.

My beds are always sunken, or at least with raised edges all around, so that once the plants get big enough, I can water by pouring a bucketful of water into the bed, and it sits there until it soaks in. Or I can do that with the hose -- not spraying the leaves, but a slow hose laid directly on the soil for a few minutes. All garden beds in my desert region are done with these sunken or surrounded beds, and traditionally irrigated by directing a canal into them and then blocking it off when full. I use buckets or a hose, and for tiny seedlings I am very careful with a very slow hose, but once they germinate I can use he flood method.

I mulch everything, and it really helps keep the soil damp and prevent it being so hydrophobic. I even put very light mulch over seeds -- not enough to block sunlight when they sprout, but even a light scattering helps keep the surface faintly damp and willing to absorb water.

Hi Jordan, when I lived and farmer in phoenix. We'd plant the rain before gardens.

Dig a dealer, like suggested above. Then add mulch. It will soften the soil and allow water to infiltrate. Rather than run off

One of the houses I lived in, the yard was planted with sod and underneath the sod was black plastic. What a terrible idea??
We hired a company to come  move the top layer and plastic. Then I'm mulched the entire area and set a sprinkler on it for about 6 months before planting. The soil underneath was beautiful. Then I dug swales for the gutters to fill and soak the water into the soil.

Happy growing

I've been thinking of the same issue with watering in my new polytunnel and I came across this thread. I'm wondering if something like Marianne's setup here might work for me.

Marianne's keyhole beds and sunken path canals

source

Marrianne Cicala wrote: We dug a ditch around the perimeter of 1 side, with several entries under the sill of the building and then the rain water runs into the hoop on that 1 side into another channel inside the hoop (a terraced bed adjoins that side of the hoop, to flow into the hoop). From there, the rain and run off (an enormous amount of rainwater runs off of the hoop house itself) goes into a channel, flows down the center of the hoop and into the keyhole beds.

I'm thinking of running the rain into a barrel and from there into wicking beds and using the overflow for some sort of passive irrigation.
I worry that with my light soil the water will just soak in locally rather than run out. I guess if you use the canals as paths they will compact down and the water will be more inclined to run along them? Has anyone more irrigation methods to share?