contemplatingmonkey - 6-7-2015 at 19:50
Hi there everyone
I have been trying to grow lettuces at my basement using the soil-less nutrient recirculating method. The problem is my lettuce keep having root rot.
I believe the problem is the Pythium (a plant parasites) in the nutrient solution. Therefore, i would like to try disinfecting my nutrient solution
with NaDCC (Sodium dichloroisocyanurate). In my application, it is essential to keep the ph level of the solution around 5.5 to 6.
1. How do i lower my ph level when i have free chlorine and hypochlorous acid in my solution without releasing chlorine gas in the atmosphere?
2. If i have to choose an acid, which acid would produce the less chlorine gas?
3. What about chlorine dioxide? I know it has to be generated onsite. It can operate from ph 5 to 10. But what happen when i try to add acid to a
chlorine dioxide diluted solution?
As you can see , my goal here is to eliminate the pythium problem and also have a safe experiment environment.
right now, i only have limited knowledge about chemistry. I am still learning. please forgive me if i have said anything stupid.
Thank you
kecskesajt - 6-7-2015 at 23:22
DILUTED sulphuric acid will work( I think)
AJKOER - 7-7-2015 at 05:40
How about an organic natural solution as someone may want to even eat your lettuce, say sunlight!
Or, being the would be lettuce is in a basement, buy natural sunlight producing light bulbs (a little more expensive). One could employ an outside
solar panel as the energy source for all your new uv light bulbs (so you are, in effect, cabling in the sunlight).
Otherwise, mold will always be an issue and a possibly deadly one at worst.
I dislike the taste of chlorinated water and most likely chlorinated lettuce as well.
If you are already using natural uv light with the issue, try a very small amount of a soluble copper salt (say, CuSO4). Copper is highly toxic to
lower organisms (mold, bacteria, fish, aqueous parasites, fish, cats,..) and just toxic to humans, so dosing is very important. It may also kill your
lettuce so test on a sample first. The total amount present in your water used for the lettuce should be under 1 mg per liter (see https://en.m.wikipedia.org/wiki/Copper_toxicity ). If you change the water, factor in also a possible accumulation effect.
If this still doesn't work, add a very small amount of chlorine bleach to say Cupric chloride (from combing CaCl2 and your CuSO4), as the Copper
source, per the reactions:
CuSO4 (aq) + CaCl2 = CaSO4(s) + CuCl2
2 NaClO (aq) + CuCl2 = Cu(ClO)2 + 2 NaCl
which gives a low dosing amount of an unstable hypochlorite and still the punch of copper. Note, I am avoiding using CuSO4 as the resulting Na2SO4 may
result in gastro-intestinal issues.
For the record, all of the above is my personal opinion and is not based on any direct experience on producing a safe food stock, so please test,
verify and proceed at your risk. Here is a source discussing the known uses of CuSO4 http://www.disabled-world.com/medical/alternative/homeremedi...
[Edited on 7-7-2015 by AJKOER]
Metacelsus - 7-7-2015 at 11:16
No! Don't add copper salts!
Ever wonder why copper sulfate is sold as root killer?
Whatever you add, make sure it won't kill your lettuce. If you also plan to eat your lettuce, you probably shouldn't add dichloroisocyanurate. I'd add
hypochlorite instead, as it's less likely to pose a health risk.
Your nutrient solution is quite likely buffered, and if it isn't, it should be. Therefore, adding small amounts of disinfectants won't change the pH
much.
Bot0nist - 7-7-2015 at 12:29
IIRC, many people that cultivate ...erm.. lettuce indoors with hydroponics systems swear by adding hydrogen peroxide solutions (not sure what amount
or concentration) to the reservoirs, in conjunction with significant aeration using bubble stones and an aquarium air pump, to prevent and treat root
rot. I'm not sure if this is applicable to your system or ailment, but it could be a relatively simple and cheap solution worth trying.
contemplatingmonkey - 8-7-2015 at 04:33
Hi AJKOER
Cupric chloride looks interesting. I will do more research on it.
Hi Ched
Why not the NaDcc? I have found this old article about NaDcc. It sounds promising =). http://plant-tc.cfans.umn.edu/listserv/1997/log9711/msg00145... I have tried applying sodium hypochlorite and calcium hypochlorite both at 1ppm
and 5ppm..and it didnt work.
Hi Botonist
i have tried hydrogen peroxide. Too little of it doesn't make a difference. Too much of it burns the root.
I would like to try applying chlorine dioxide. because it is 10 times more soluble than chlorine in water.
like mixing sodium chlorite with hydrochloric acid or citric acid:
5NaClO2 + 4HCl -> 4ClO2 + 5NaCl + 2H2O
this looks "safe" to me..or is it?
Metacelsus - 8-7-2015 at 11:17
These reports:
http://www.who.int/water_sanitation_health/dwq/chemicals/sec...
http://www.inchem.org/documents/jecfa/jecmono/v52je21.htm
explore the safety of NaDCC, and it doesn't look too bad. I guess it might be fine to use in hydroponics. It would probably kill the plant before it
became a health hazard.
diggafromdover - 8-7-2015 at 11:39
I've sworn off "lettuce", it gave me the munchies...