Water conservation for gardens/greenhouses.

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Aerindel

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Here in the northwest, we have had an epically dry winter. This is a big deal because we normally get very very little rain in the summer, so irrigation is almost completely dependent on winter snow.

Now, I am 'lucky' (it wasn't by accident) to be the first private property, that an irrigation ditch flows through. With water rights, I have access to millions of gallons of water all summer, and with thousands of acres watered by dozens of people, there is significant 'push' by other people, to keep the water flowing.

The problem is, for years, the ditch has been turned on later each year, and turned off earlier.....(when we moved her, it was on year round)

Water rights aside.....the rights don't put water in the ditch when the supply lake runs out. I have a 'feeling' irrigation water is going to be limited this year like no other.

Now, I have very poor soil here, living atop a terminal moraine (think a giant gravel pile left over from the last ice age) so almost all my growing is done in potting soil, in my greenhouse. For bots I use grow bags, because they are the only potting solution I found, that lasts long term. Plastic pots break down and crack in the sun, ceramic breaks when it freezes, wood rots.

Because of the climate, I need the greenhouse to have a chance at growing most vegtables during the short growing season.

The problem comes when the ditch does get turned on until a month after I start planting, and gets turned off a month before the first frost. Normally I manage to make due with well water during these periods, buts its not easy and puts a strain on the well to pump that much water each day.

Currently, my greehouse is watered with microsprinklers in each pot, on a timer, and uses about 250 gallons per day.

I have two ideas. First, is to line all my grow bags, with plastic sacks, to retain water. I think this could make a big difference, although I've never tried it before. I don't know if this would harm the plants, one of the supposed advantages of grow bags, is the increased drainage.

My other idea, is to start rain water collection from the greenhouse roof. Usually during that first month of spring, there is plenty of rain. None of it does the greenhouse any good however. I am thinking about trying to install gutters on the sides of the greenhouse (standard metal framed half cylinder design) to collect rain water, and then use a small electric pump, to run my sprinkler system (normally gravity feed from a 500 gallon hydraulic ram supplied tank)

It's annoying to build a system that intensive...that I know will only even work about one month a year, but for that one month, I suspect I could keep things watered just with rain, if I also reduced water loss.

Thoughts? Ideas? This is rather 'new' to me actually, as I've been used to virtually unlimited cheap water.....but I think I need to pro-actively prepare for less water going forward.
 
...My other idea, is to start rain water collection from the greenhouse roof....trying to install gutters on the sides... annoying to build a system that intensive...

Since yer considering 'passive', well.. Sounds 'silly' at first glance, but What about, ie: https://www.homedepot.com/p/Summer-Waves-45-in-Round-7-9-in-Deep-Kiddie-Pool-P60000130/317025815 ..but x10? 🤔

(or, even ie: https://www.ebay.com/itm/305357617336 x5-6? (~2x the collection-volume of the others, there.. 🤔 And place around spots on the prop where you'd be surest to get a nice, even rainfall, to fill 'em up quick. (Could even put a couple up on Any 'flat-roof' ya've got, and plumb a drain > poly barrel pvc-pipe.. So'z not to Collapse yer nice roof.. ;)

..And, if 'leaves / bird-scootie / general plant-funk', etc was a Concern (for the pump(s) can get some: https://www.skeeta.biz/skeeta-mosquito-netting-no-see-um-netting-fabric-mesh.html ..to make 'screen covers' (that stuff makes an Excellent 'coarse filter' for water-catchment designs👍 Keeps near-Everything Out, and easy to back-wash / clean, etc. Great stuff.

Just a thought, as yah.. 'Gutters' seem a major PITA, and Far less 'yield' than something like this. Heck - if the 'wallet can stand it', get 20x! That'd be some Substantial 'passive-volume collected' in aggregate, methinks.

jd
 
...I just looked up the average rainfall and calculated it out over the greenhouse roof and..

Hmm, well.. Using the 'eBay listing' one as example, I calc its capacity to be ~564 gals.. IF you could Rainfall-fill 1x of those 2x per month - but have 5-6 (or even 10x) or 'em around the prop... Might that not be 'worth it'? 🤔 (especially considering the 'ROI' (cost + Labor (to set up) vs the 'Gutter' scheme..) Plunk 'em and Leave 'em.. and just Pray for Rain. :)

.02
jd
 
Hmm, well.. Using the 'eBay listing' one as example, I calc its capacity to be ~564 gals.. IF you could Rainfall-fill 1x of those 2x per month - but have 5-6 (or even 10x) or 'em around the prop... Might that not be 'worth it'? 🤔 (especially considering the 'ROI' (cost + Labor (to set up) vs the 'Gutter' scheme..) Plunk 'em and Leave 'em.. and just Pray for Rain. :)

.02
jd

Well, unless I want to hand water a hundred pots.....it needs to be a plumbed in solution. My thought was to gutter in a 200 gallon tank, with an on demand pump. I have limited electrical down at the greenhouse site, to run the electric fence, so running one of those little RV pumps would be practical.

And keep in mind, for the whole month in question, average is 3" of rain, so just living containers out in the open, would mean that for the whole month, they would each only be 3" deep.
 
Couple of ways to approach your problem. I have lived off rain collection for over 60 years. You have the collection side of the system and the storage side of the system. I have built concrete, and wood cisterns. In addition I have installed wood, stainless steel, steel, and plastic cisterns up to 5,000 gallons each. We put up an above ground swimming pool that we lived off for several years. I want to say it held 14,000 gallons but that was too long ago to swear to. My point is that a cistern is just a battery. You could fill a cistern from your stream. If you use 250 gallons a day and you need to go 30 day then you need 7,500 gallons of storage. We have an old stainless tank off a water truck. I think it is 3,500 gallons. a couple of those would do the job. A lot of people here have 10’ to 12’ culverts 10’ long set on end with 6” of concrete plugging the bottom.

Some desert people build rain decks, basically a roof on the ground. That never made sense to me. With a few uprights you could build a pole barn and have storage as well as rain catchment.

You could also go hydroponic or use hydroponic ideas. One trick is to grow in media not soil. They use cotton string poked in the bottom of the media and hung into a sump. Some use plastic bags of media. It stays moist but doesn’t flood the system and uses minimal amounts of water.
 
..My thought was to gutter in a 200 gallon tank, with an on demand pump. ...for the whole month in question, average is 3" of rain, so...

Hmm, well.. Then maybe - if yer gonna go thru the Effort to gutter - Could you 'force multiply' by setting up 'Tiered' gutters, say 3-4x each Side, 'stair-stepped' (but spaced, so they don't 'roof' each other) and each draining into the other (with the 'Lowest', on each side (still Above yer catchment-tank) 'Y'd into the tank? 🤔

jd
 
Hmm, well.. Then maybe - if yer gonna go thru the Effort to gutter - Could you 'force multiply' by setting up 'Tiered' gutters, say 3-4x each Side, 'stair-stepped' (but spaced, so they don't 'roof' each other) and each draining into the other (with the 'Lowest', on each side (still Above yer catchment-tank) 'Y'd into the tank? 🤔

jd
No need...one each side of the greenhouse would collect all the water that hits the roof.
 
Water collection may not be worth it at all. I just looked up the average rainfall and calculated it out over the greenhouse roof and we are talking less than 1000 gallons yield for the whole month.
First of all, if it's to be an automatic set up, it sound like you will have to invest money to make it as hands off as possible. Also- (and please, I don't mean this in a rude way) you might need to change your mindset. Any water, no matter how little, is useful. I originally come from a country where very drop is precious, and I still think that way, even though it rains here most of the year. My polytunnel is away from any water source, and even my house is not on mains, (I have my own old well, but with six adults in the house) so with the summers becoming hotter, I've rethought what we do.
My poly has gutter down one side into a 1,000 litre IBC. I need one on the other side but held off as we were going to move the poly. It's hosed into the poly.
I also have an old bath that collects run off also.
Off my garage and sheds I have water butts also.
I don't use chemicals for clothes washing, so my washing machine water goes into a barrel which is used to water veg also.
I keep a bowl in my sink to collect waste water also.
My ensuite shower is piped into barrel with gravel and sand for filtration, and it goes into the drain beside me usually, but the pipe can be swung into my veg garden if I need it. Where I used to work had a restaurant that would throw out huge lidded buckets that I started to take, they are placed around the place to collect run off from overhangs etc. Its amazing how quickly they fill up. Basically it's little wins; if I have to bucket, so be it- keeps me fit!
Best of luck with it, hope the rains come soon.
 
The bags are a nice idea, until root rot sets in... Have you thought about a water collection system under your pots? Something that could collect your excess water and deliver it to a storage location for reuse? If you are using 250 gallons of water per day, you must have some greenhouse, and if you have just a 2 week water reserve you would need about 3500 gallons of storage that could be filled using a combination of rain water, your canal, and any reuse water you collect, but storing water from that many sources you would need to figure out some sort of filtration system to keep from clogging your emitters. I use an irrigation boost pump to move water from my rain barrels to my distribution system and that can provide sufficient pressure to use drip irrigation with the rain barrels. If your temperatures drop too low in the winter you will need to figure out how to protect your system from freezing (I have to drain mine). I think I would start with conservation, using the least amount of water required to get the yield that you need.
 
The bags are a nice idea, until root rot sets in... Have you thought about a water collection system under your pots? Something that could collect your excess water and deliver it to a storage location for reuse? If you are using 250 gallons of water per day, you must have some greenhouse, and if you have just a 2 week water reserve you would need about 3500 gallons of storage that could be filled using a combination of rain water, your canal, and any reuse water you collect, but storing water from that many sources you would need to figure out some sort of filtration system to keep from clogging your emitters. I use an irrigation boost pump to move water from my rain barrels to my distribution system and that can provide sufficient pressure to use drip irrigation with the rain barrels. If your temperatures drop too low in the winter you will need to figure out how to protect your system from freezing (I have to drain mine). I think I would start with conservation, using the least amount of water required to get the yield that you need.
Yes. Drip irrigation uses less water.

Use your ram pump to fill swimming pool for storage?

Plastic or mulch on top surface of soil to reduce evaporation.

Ben
 
Not bad ideas.

I use micro-sprinklers instead of drip irrigation because its more controllable. I have it all on a timer system that I can change as needed. Usually I have the pot system run for 1 minute, every two hours. But I can up that as much as I need. (parts of my garden use more, this is just the grow bag section.

I titrate the system until I have minimal water running out of the bags, but because the bags lose so much to evaporation, if I don't run water often, they dry out.

Filtration is already solved, as my normal water supply, is an open irrigation ditch running through the woods. I've had a system to filter the water so my sprinklers don't clog for many years. I figure my rainwater would just go through the same system.

Yes, any system would be automatic. My hoop house is a hundred yards from my house and 50 vertical feet below it. Sometimes in the summer I don't get down to it for a couple weeks at a time. This was a huge benifit last summer when because of a forest fire, I ignored the greenhouse for almost a month. It was a little wild and overgrown, but fine on its own all that time.

I already have a greywater system, all household water runs outside into a rhubarb bed.

Not that it matters very much, my greenhouse uses more water in a few days, than my house does in a month.
 
I posted somewhere else about collecting waste water, water from the sink & show that would normally go down the drain. With that water I can keep our little outdoor fountain running all summer & we live in more or less a desert. To give an example on summer days our lake can lose 4 feet a day because of evaporation.

As far as collecting rain water, I do that too with 8 water barrels. Sounds like you grow a LOT more than I do so I'd check out video's on U-Tube. If it's dry there & doesn't rain much if I were you I would think BIG. Forget barrels & do a one time investment on a black plastic cistern type container. You can get the size you need & then you just have to make sure to collect all the water you can. Again, I suggest U-tube because some people live in a total desert environment & are able to collect enough water to be self sustaining.
 
Catch water off all your roof & reuse it.
 
My barrels came from 4 sources, (I bought cheep one from a bottling plant), I bought nicer 65 gallon barrels online, I bought blue food quality barrels online, I got hand-me down barrels that had soap and anti-freeze from someone who worked at a rail road maintenance center. The difficult part was installing bottom bungs on each one and then connecting them all to a central manifold that feeds an irrigation boost pump. All of my barrels are on 4X4 cribbing (2 layers thick) shimmed so that the tops are level. I use a sight glass (1/2" clear plastic hose clamped to a vertical post) to monitor my levels. All of my downspouts feed into a barrel that is higher than the main array (it acts as a screen and sand trap). 1 cubic foot of water is about 7 and a half gallons, so it doesn't take a lot of rain off a typical roof to give you a lot of water. A quarter inch of rain off a 1500 sq-ft house will give you about 230 gallons...
 
Catch water off all your roof & reuse it.
My roofs are asphalt composite so no good for gardens. I also live in a three story tower so my roof area is a third the size it normally would be for a single story house this size.
 
Today was trash chore day, I threw out all of the "old lettuce, spinach, and tomatoes". Then I harvested fresh replacement stock. As I was washing the fresh stuff at the sink my mind went back to the days of my youth watching carrots being harvested, cleaned, sorted, and bagged. I remember the trucks would come from the field and dump the carrots into a swimming pool sized tank of water and from there they were lifted out by conveyer belt to a washing area... The people at the washing area would spray off the carrots using a hand sprayer... Now to relevance, I don't know if they were using fresh water, water pumped from the "tank", or if it was some sort of filtered recycled water.

It seems to me that the off-grid folks here might have a system that they use and I would be interested in learning about that.
I can envision a wash station with a drain/strainer feeding a filtering tank, and having that feed a reservoir and pump feeding a hand sprayer at the wash station. But, I am assuming that someone here has developed an elegant solution that really works....
 
When I lived in the ...bush... we always collected rain water in barrels and totes.. We were growing zone 2 = 55 day average season, and rain water was a big help to make the best of things to the ..average first frost date..
My 5 cents of experience..
 
Didn't get any water catchment system in time to catch the spring rains, and they are going to end anytime now.

I have been double bagging my grow bags with plastic sacks with the bottoms cut out, I'm about 3/4 through that job. Should be warm enough in a couple weeks to start moving the tomatoes out there.
 
My rain barrels. When I started off I bought them from Sam's & paid around $120 for them. They were "ok". But as I used them & learned more I started checking around. I ended up buying what is basically a black garbage can with a tight fitting top & one spigot. I think I found them on Amazon? They cost about $60? I love that they are cheaper & hold a good amount of water & that they are black (to cut down alge growth). The only improvement that I would make to them is to add a another spigot. Having 2 spigots gives you a lot more options on what you can do with them.
 
I have most of my parts now to build my automatic watering system off the rain-barrel array. If it does not rain, I may get it done this weekend.
 
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