greenhouse/garden water systems - Orchid Board

james mickelso · #1 10-23-2011, 09:51 PM

hi all you addicts, another question. I use water from my household faucet to water my orchids. The total dissolved solids run about 500-650 ppm. I don't water my orchids with a hose due to past problems with root rot and other rot problems. So I use a 5 gallon bucket and dip each. I dip about 30-50 of them and then water my orange tree with it and refill the bucket. Orchids grow resonably well but could be better. So I'm researching RO and distilled water systems. Can any of you help with information about what you have used and what has worked? I am looking at units that deliver around 50-100 gpd. Would fit in my greenhouse under a bench and not cost me an arm and a leg. Arms are ok but not both. How long do your cartridges last before you have to buy new ones? Do you store the water in a tank or can you water from a hose? Any other info would be greatly appreciated. Oh, I don't have show quality anything. I have about 300 or so cast offs from shows and dumpsters. Probably lots of bad viruses, funguses, and bacteriaal rot. But they all seem to want to grow despite it all. Thanks.

orchids3 · #2 10-23-2011, 10:10 PM

Your post is interesting. I dont use a RO system so will leave that for someone else.

A few questions come up - is the water from your house differant than the water from your hose? If so do you use some kind of softening system in the house? Is the water from your hose too cold?

dounoharm · #3 10-24-2011, 02:26 AM

i use plain old tapwater, no softening system, in both my oklahoma setup and my north carolina greenhouse.....no problems in either place....i think if you are using the same bucket to water all your orchids you will be spreading nasties from one to another real fast....ray will be along shortly to educate you on ro water i am sure....

Discus · #4 10-24-2011, 06:11 AM

Depending on the species/hybrids you grow, that's a pretty high TDS reading, so RO will probably really help you out. You won't need RO water for the rest of your garden plants though, IMO. (although starting off with a really low TDS lets you add more fertiliser to the water without harming the plants).

If you want to water with a hose, you can install a pump in a sump tank; the RO continually tops up the tank (installing a float valve on this may be a good idea), and then you can water from the tank; RO units are generally pretty slow, and definitely not something you want to use a hose with. 50-100GPD is quite a lot of water.

I know First Rays sell quite a lot of what seem like pretty good value RO units. Take a look here.

keithrs · #5 10-24-2011, 12:42 PM

My total TDS is about what you have and I switched to RO water about a year ago and its the best move I have made!!! Sure the TDS is where very high for some of the plants I grow but to me the best thing it did was bring my PH down to around 6 or so. PH plays a huge part in how well your plants can receive nutrients. I have yet to replace my RO filter. I backwash it once a week. It important that the membrane doesn't see air after its wet. I fill a 55 gal barrel with a float on it so I fill it automatically. To know when to change your filter your going to have to monitor the TDS coming out. My TDS have not been higher the 22 TDS, so I feel safe for now.

Fish guys know alot on RO systems if you need info on which to buy. Ray will help you out too!

glengary54 · #6 10-24-2011, 04:17 PM

James - if what you say about your collection having, virus, fungus and rot issues is true, watering by dunking them into a pail is the worst thing you can be doing. I would be more concerned about that than my water quality for now. Sounds like you need to start a regular routine of spraying fungicides and bactericides to get your collection healthy and STOP DUNKING them.

A RO systems would be great but it is not going to cure your cultural problems.

Masdyman · #7 10-24-2011, 07:19 PM

Your TDS is very high, your water tds alone is more than my RO/feed put together. With TDS this high it doesn't leave anything left to add feed and if you have been adding feed to this is probably the reason you have poor roots. I haven't looked back since using RO and would never go back to tap or rain water.

You must use a feed with RO water in mind ie MSU, RO water normally falls between PH 6.0-8.0, mine is around 7.0 and goes more acidic as the filters deteriorate. I found that when the RO water was mixed with the feed and the PH is at the lower level of say 5.5 or below then this is the time to change filters, once you renew the filters the PH should be at a higher level again. I seem to think that the feed is PH stable to a point, but mine dropped to and below 5.5 when the RO filters were in need of a change, once replaced the RO/FEED mix falls within limits 5.5-6.5 without any need to adjust PH, mine is normally around PH 6.0 or just below.

orchidsamore · #8 10-24-2011, 08:14 PM

I feel I have to chime in here.

I am a commercial grower and my TDS is 1700 from my well. The orchids do well. During the summer we get 2-4 hours a day of rain almost every day. Root rot is a minor problem.

TDS does not cause root rot. The pythion fungus is present everywhere and the result of poor potting medium more than anything else.

That said, RO water is excellent. However, it is an extreme waste of water using 4 gallons of water to make 1 of RO. There are some small systems that claim to be waste free, but I have no personal experience with them.

Then a commercial size system can be very expensive. A larger grower than me wanted one and the $85,000 price tag turned the owners off.

keithrs · #9 10-25-2011, 10:12 AM

You sure you don't mean 170 TDS? 1700 is unheard of for raw water. I bet Masd. and such don't do well for you.

Ray · #10 10-25-2011, 10:19 AM

As Discus was kind enough to point out, I sell a lot of RO systems.

There are some points to keep in mind.

They are usually rated at 65 psi and 77°F inlet water temperature. Lower levels of either reduces the output. I have a chart showing the effect: PDF Here

Even at 100 true gpd, that's only about a cup a minute - certainly not sufficient flow to water with, so you'll need a storage tank and delivery pump. For years I used a 55-gallon drum (free from the car wash) and a submersible pump.

Most average 4 gallons of flush water per gallon of pure produced. I have seen some rated are 2:1, but for much more money. I recently saw a 1000 gpd unit rated at 1:1, but if you reduce the flush water flow, you likely have to replace membranes sooner.

"Zero-waste" RO systems utilize a booster pump to push the flush water into your household hot water lines. Most folks use it to water other plants; I use it to refill an artificial pond outside of my greenhouse.

Replace sediment filters every 6 months, charcoal every 12, membranes ever 24. I provide sufficient sediment and carbon filters to carry you through that first membrane change, so you can start fresh with all three types then.

If you have more questions, feel free to call me at 888-283-5094.