Aquaponic Gardening

A Community and Forum For Aquaponic Gardeners

Hey there,

Can anyone give me input as to what is wrong with these plants?  I did have spider mites but I believe I have gotten rid of all of them. My AP system in indoors.  Is this a light issue, nutrient issue, ph, or insect issue?  I'm not very knowledgeable when it comes to gardening - kinda learning as I go.  My PH does tend to run on the low side - around 5.

Views: 553

Attachments:

Reply to This

Replies to This Discussion

Have you tested your ammonia, nitrite and nitrate lately?

A pH of 5 might be too low for the bio-filter to still be working.  You really want to keep the system buffered enough that the ammonia doesn't spike again.

 

The damage to the leaves could be from before when the spider mites were around or from whatever you used to get rid of them.  It could also be from lack of some nutrients due to pH being too low (too low or too high both cause issues.)

Or if it is a new system and hasn't built up a good reserve of all the trace elements it might be worth while to add a little maxicrop.

 

It is hard to tell just from the two pictures what the problem really is.

Do you have a fan blowing in the room? And are the lights closer to the plants normally?  It does seem rather dark in there for good plat growth.

I have a system with low pH issues and also found the pepper leaves to look a bit mottled with black dead bits.  Fruit was also not fast-developing at all.  I have been trying to lift the pH gently up from low 6 to around neutral.  This process is on-going, for about a month now.  Nutrient availability was an issue and the nitrification process will be depressed for you with the pH of around 5.  I would suggest trying to move the pH to 6.8 to 7 over a period of at least 3 weeks.  This is because the pH swing up will make the amount of ammonia in the system more toxic, and the nitrification cycle must be given a chance to adjust.  The process will be very depressed right now.  Even with a careful approach, you may have some losses.  My celery keeled over, and the egg plants dropped their developing fruit.  Overall though the nutrient availability in my system has improved and the pepper leaves are not so blotchy.

How much Maxicrop?  Is it safe for the fish?  Right now, I have rhubarb, peppers, rosemary, basil, tomatoes, and broccoli.  But nothing seems extremely healthy but actually might be getting better now that mites are gone (at least I think they are).  

What's the best & safest way to raise PH?  Did I hear something about shells or eggshells?  

 

Also do LED lights work?  The other ones seem expensive to run...I might not have enough light?  Wasn't sure how light deficiency would manifest itself in plants?  Here's what my test results were today :  PH = 5.25,  Ammonia = .6 (which was just one level above zero),  Nitrite = zero,  Nitrate =  approx. 20.  Does that sound about right?

pH can be raised very slowly with shells, oyster shells or other things used as chicken grit from the feed store, egg shells (if you wash them), or garden lime dissolved in water.  Potassium bicarbonate can also be used.

More quickly you can raise pH using hydrated lime or slaked lime.  Be careful with these and start working with like 1/8th teaspoon amounts till you figure out how much it will shift the pH.  Perhaps best to take a 5 gallon bucket of system water add a bubbler and put in a small measured amount mix and wait an hour then check the pH again.  Then using those amounts extrapolate how much you think it will take to shift your whole system water 0.1 in pH and use like half the amount and then check the pH the next day to see what it did.  Then you can move on from there to hopefully safely and slowly work the pH back up closer to 6.8.

In a real pinch even baking soda can be used but it adds lots of salt so generally should be avoided.  I used a tablespoon in a 300 gallon system once and it brought the pH up like 0.4 way too fast so be careful.

 

6.8 is a handy pH since it gives you time to notice if the pH is dropping below 6.5 so you can take action before it gets below 6.

 

Egg shells and shells probably won't raise your pH fast enough to save things at this point.  Shells are handy to add to a system once you get the pH above 6.5 and they will help buffer to keep the pH from dropping too low but using them is not very exact so you have to have them in a manner that you can remove if the pH goes too high or add more if they are not keeping the pH up high enough for you.

 

As to the LED lights, you need lots of them and they need to be very close to the leaves of the plants to be effective, kinda like the florescents you have to have them within a few inches of the leaves and move them up as the plants grow.  lumen per lumen and watt per watt, if you have more than a very small growing footprint and all same size small plants, the Metal halide lamps are probably as cost effective as the others at this point in time.  A single 1000 watt metal halide can light up a much larger growing space and be higher above the plants.  Florescent fixtures can only light up about the same footprint as the fixture takes up and it has to be right down on top of the plants.  I believe most led lights are similar in needing to be close to the plants and they are still really $$ though the energy consumption is low.

I'm really not a lighting guru since I've got florida sun to work with.  I recommend AJ's group for learning more about indoor growing under lights.

http://aquaponicscommunity.com/group/artificiallighting

Do you find that Maxicrop with Iron effects your pH?

 

You mention hydrated lime. From a nursery or feed store? Are all types safe for AP?

 

Currently at about 6.2 in both 40 gallon and 110 gallon tanks. Thinking about just adding oyster shells at this point.  I've heard marble chips are good for calcium??

 

 

TCLynx said:

pH can be raised very slowly with shells, oyster shells or other things used as chicken grit from the feed store, egg shells (if you wash them), or garden lime dissolved in water.  Potassium bicarbonate can also be used.

More quickly you can raise pH using hydrated lime or slaked lime.  Be careful with these and start working with like 1/8th teaspoon amounts till you figure out how much it will shift the pH.  Perhaps best to take a 5 gallon bucket of system water add a bubbler and put in a small measured amount mix and wait an hour then check the pH again.  Then using those amounts extrapolate how much you think it will take to shift your whole system water 0.1 in pH and use like half the amount and then check the pH the next day to see what it did.  Then you can move on from there to hopefully safely and slowly work the pH back up closer to 6.8.

In a real pinch even baking soda can be used but it adds lots of salt so generally should be avoided.  I used a tablespoon in a 300 gallon system once and it brought the pH up like 0.4 way too fast so be careful.

 

6.8 is a handy pH since it gives you time to notice if the pH is dropping below 6.5 so you can take action before it gets below 6.

 

Egg shells and shells probably won't raise your pH fast enough to save things at this point.  Shells are handy to add to a system once you get the pH above 6.5 and they will help buffer to keep the pH from dropping too low but using them is not very exact so you have to have them in a manner that you can remove if the pH goes too high or add more if they are not keeping the pH up high enough for you.

 

As to the LED lights, you need lots of them and they need to be very close to the leaves of the plants to be effective, kinda like the florescents you have to have them within a few inches of the leaves and move them up as the plants grow.  lumen per lumen and watt per watt, if you have more than a very small growing footprint and all same size small plants, the Metal halide lamps are probably as cost effective as the others at this point in time.  A single 1000 watt metal halide can light up a much larger growing space and be higher above the plants.  Florescent fixtures can only light up about the same footprint as the fixture takes up and it has to be right down on top of the plants.  I believe most led lights are similar in needing to be close to the plants and they are still really $$ though the energy consumption is low.

I'm really not a lighting guru since I've got florida sun to work with.  I recommend AJ's group for learning more about indoor growing under lights.

http://aquaponicscommunity.com/group/artificiallighting

I've never used maxicrop with iron.  I have noticed that some other types of iron supplementation can affect pH though.

 

Hydrated lime or quick lime is safe but really strong.  You have to be very careful with it since it is very easy to overdoo.  You don't want to move the pH fast.

If using oyster shells, limestone or marble chips or anything of that sort, use them in a mesh bag or something so you can remove them as needed if the pH rises too high.

 

I have been alternating between spoonfulls of potassium bicarbonate and soaking a bag of chicken grit in my tower system to try to keep the pH up without raising it too high or getting too much calcium in relation to potassium. 

 

Allisyn Wood said:

Do you find that Maxicrop with Iron effects your pH?

 

You mention hydrated lime. From a nursery or feed store? Are all types safe for AP?

 

Currently at about 6.2 in both 40 gallon and 110 gallon tanks. Thinking about just adding oyster shells at this point.  I've heard marble chips are good for calcium??

 

 

Elaine, I have about 2550 gals in my home system, and  add aprox a 1/8 - 1/4 cup of maxi crop with iron about twice a month. When I have a full system of young lettuces growing.... I also use a liquid iron product from Lowes. I use about the same amount of it also.

Allisyn,  I add so little, I've never checked to see if the maxi-crop or the iron changes the PH....?    ( 1/4 cup to 2550 gtals of water)

I add them, after my swirl filter, but before the media and raft beds. By the time it gets back to the fish...'if' it did change the PH....they don't seem to notice.

Everyone seems to love chelated iron and lime on this forum. I use maxicrop with iron once a week and I'm still struggling with deficiencies, but I think much of that could be over planting. Does anyone use Maxicrop with iron AND chelated iron/lime? What about KOH I see everyone talking about? Where can you get that? Best as foliar or just put it in the beds? My pH is very low at 6.0. As per another post, I'm going to add marble chips to help bring that up, but any advice is appreciated. Seems like a lot to be adding. Are there test kits for these elements? What are the appropriate levels?

Hi Alison, MaxiCrop with Iron, if I recall correctly is a product that contains iron sulfate as the iron component, not any form of chelated iron...That being said, with a pH of 6 and a decent quality fish food it's weird that you should be experiencing iron deficiencies while using that product? At a pH of 6 you really strange that you would need chelated iron (especially since your using the MaxiCrop) Are you sure it's iron? If its yellowing between the veins of OLD leaves you might want to add some Epsom salt for the magnesium...

You might be waaay better off using KHCO3 (potassium bicarbonate) rather than KOH (potassium hydroxide) for a bunch of reasons...you don't really want to spray the KOH on any leaves either ...I'm guessing that you just got the two mixed up. Here's the stuff I've been using...from the people I got it from.

http://www.organic-gardening-shop.com/Agorganics/product_details.as...

In order to buffer up their pH poeple will alternate between using KHCO3 one time and a calcium base (like hydrated lime) the next time...it's also good as a foliar spray adding K and acting as a fungicide...good stuff. And from the sound of it, it might be time to raise your pH a bit. (lime or KHCO3).

The chemistry behind KHCO3 is much more simple than marble chips. You don't need a test kit, just a way to measure pH when buffering...plants will use up K about as fast as they'll use up nitrates (some like cucumbers even faster). For foliar spraying 4 teaspoons to a gallon of water is fine (both for funcicidal properties and to feed some K to the plants).

Thanks. I'll look into the stuff you recommend. I've heard Epsom salt in other posts. How do you apply it? Regular old salts from the store? I feed aquamax 4000 so I should be good there. I think my fish ratios are a bit low, so that probably has a lot to do with it. I might not be using enough Maxicrop because my water never changes color. I use about a capful in the beds for the 110 gallon tank.
Ordered and on it's way! Shipping was more than the product :( let me know how you use yours. Looked like a folier application... Please educate me on the lime. I wanna get this garden running and looking good. Getting ready to pull the cukes that seemed to do what eveyone elses do, great the just terrible very quickly. Got 5 large cukes off of it. Now, if I could just lose that ONE tree and bring in some sunshine...

Yeah, it's sold as an organic fungicide for dirt gardening, but you can use it in the same way you'd use hydrated lime to raise your pH...Allisyn, have you ever buffered your systems water pH up before? With anything (top up water counts if your water is "hard" ...meaning it has high carbonate alkalinity...meaning it has a 'high-ish' pH...those terms for all intents and purposes are used interchangeably...

If your pH test kit only goes to 6 and your test kit says 6 you could really be at 5 or anywhere below 6. You really have no way to know, and that would be bad. Too much below 6 and your bio-filter could suffer or crash. I have a number of pH test kits and a digital meter, but I know many use an API kit that only goes down to 6...That's why I asked about the buffering. Just trying to get an idea of where (pH wise) and how you run your system. If this is your standard MO, or if you need to take some 'emergency' action to immediately start raising your pH with carbonate alkalinity with whatever you have on hand (like baking soda)...

See for every mg of ammonia that your bacteria turn into nitrates, they 'consume' 4.5mg of oxygen and 7-8mg of carbonate alkalinity...this is why your pH in an AP system is continuously falling...because of nitrification the process itself.

This is why you need to buffer you pH regularly. If you let it fall too much below the mid to lower 5's the bio-filter tends to crash and burn. But if you have a test kit that only reads to 6...See where this is going? That's why I ask. 

I can't view your profile page, so I don't know much about your system.

I'd be happy to share whatever I know about plant nutrition, Epsom, cukes, potassium, lime maxicrop, whatever...but we should probably get a handle on what's going on with your pH first as that would be most important right now.

Reply to Discussion

RSS

© 2021   Created by Sylvia Bernstein.   Powered by

Badges  |  Report an Issue  |  Terms of Service