Aquaponic Gardening

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Sylvia, my husband & I came to visit you a few months back.  We really enjoyed seeing your setup.  We are trying to make our system work but I keep having problems with the plants.  At first it was aphids so we bought some ladybugs and that seemed to help but they slowly all died.  Now I think it might be spider mites.  I have been spraying with neem oil and seems to help.  My plants just seem to die off before they finish producing.  I'm not very knowledgable about gardening yet.  I've attached some pics to see if you might have some input or advice.  Not sure if my problem is bugs, not enough light ( our system is inside), or something else??  The peppers seem to produce but then they just wither up before they are mature and the leaves are falling off.

I'm kinda frustrated at this point.  If I need more light, I'm just not sure the expense in electricity can be justified.  The fish seem to be fine.


Would appreciate any advice,

Michael & Elaine Sanders

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Thanks Sylvia...I'll try getting a fan.  Here's another picture.  It seems like the bugs are all dead.  They are not moving.  Do I have to pull all the plants and start over?  Do you think there is something more going on?  Would the insects make the peppers shrivel before they are ready & the leaves drop off or do you think the pepper problem is the neem oil or lack of light?

Sylvia Bernstein said:

Sorry for not jumping back in here earlier, Elaine.  Busy day yesterday.  A ceiling fan won't do it because that is mainly pushing the air down, which doesn't really affect insects because they tend to live under the leaves.  What you are trying to do is emulate a constant breeze, which the insects find pretty annoying.  Needs to be a horizontal breeze.  I use a couple inexpensive oscilating fans from Target.  Good air circulation will also help with mildew and fungus.


I totally agree with AJ - if you are seeing spider webs you are screwed.  I just ripped out every strawberry plant in my greenhouse a couple weeks ago because of GD spider mites.  You have to go into pretty toxic territory to get rid of them once they are at that stage, and I'm not going there.


I use insecticidal soap for spot treatment and neem every other friday in the trouble spots, and beneficial insects as I think about it.  Generally works...except with spider mites    If you go to our website under Insect Control you can see some products that I'd recommend...and use.


that should be safe for fish right?

TCLynx said:

I wonder how effective something like DE is against spider mites.  Really dusty to use inside the house though.

This is from wiki...

Various insects and predatory mites feed on spider mites and provide a high level of natural control. One group of small, dark-colored lady beetles known as the "spider mite destroyers" (Stethorus species) are specialized predators of spider mites. Minute pirate bugs (family Anthocoridae), big-eyed bugs (Geocoris species) and predatory thrips can be important natural enemies.

A great many mites in the family Phytoseiidae are predators of spider mites. In addition to those that occur naturally, some of these are produced in commercial insectaries for release as biological controls. Among those most commonly sold via mail order are Galendromus occidentalisPhytoseiulus persimilisMesoseiulus longipesAmblyseius fallicus, and Neoseiulus californicus. Predatory mites eat adult mites, their eggs, and all developmental stages between. Predatory mites can consume as many as 5 adult spider mites per day, or 20 eggs per day (as many eggs as a female spider mite can lay).

I also remember reading somewhere that once there is no more food source i.e spider mites, most of the above mentioned critters will then cannibalize themselves...might be worth trying out..? 


Sorry I didn't see this back when you posted it.  I must have gotten bogged down.  DE (provided you are talking feed grade and not the swimming pool stuff) won't hurt fish, it is the powdered fossilized remains of diatoms which were microscopic sea creatures.  It hurts insects by scratching them basically and they die from dehydrating through the abrasions.  This is of course more effective against the small softer bodied insects than it is against things like ants and it is also more effective in a dry environment so has some drawbacks near aquaponics where there is ample water near by.

It is fairly safe stuff to use as it isn't toxic, anyone who eats any grain products probably eats some every day as they use it in grain storage to deter weevils and other insects.  People often use it like a flea powder on their pets.  It's dusty stuff though and you want to avoid breathing lots of dust or getting lots of it in the eyes.  Main drawback is it will also hurt beneficial insects.


Elaine Sanders said:

that should be safe for fish right?

TCLynx said:

I wonder how effective something like DE is against spider mites.  Really dusty to use inside the house though.

spidermite is an absolute nightmare, i wish you the best of luck if you have them, although i couldnt see any webbing on your pics, the best thing we find them for is the predators Phytoseiulus Persimillis, these are a small highly voracious predatory mite slightly larger than a spidermite. also if you can raise the humidity and cool the room more to under 24 celsius this will really slow down the breeding of the spidermites and increase the activity of the predatory mites. we also found on severely infested plants with lots of webbing that physically removing the mites with the means of a vacuum cleaner nozzle can help to reduce the numbers prior to releasing the predators, give them the upper hand from the off!


good luck!

Crap. I have spider mites. I have been pinching off areas of the plants where I see the webbing, but it looks like I need to buy some predatory mites ASAP.

Hi Windy, in my experience pinching off the webbings isn't going to help a whole lot in the long run...if you can get predatory mites (larvae) that would surely help, but if there is webbing already you need to act a bit faster...this past fall/early winter I experimented a bit and found that a the  following worked the best

2% tea tree oil + 1% lavender oil (really though any essential oils seemed to work ok) 0.5% dish soap the rest is water. Mix well and spray. Try to get the undersides of your leaves, since this is where most of the mites as well as there eggs are at. Even spraying str8 water will kill some (maybe 20% of them), they do not thrive in humid/wet environments) The oil clogs their skin (which they breathe through) and they suffocate right there on the spot.

Cover your fish tank, and if you can, otherwise protect your grow beds (within reason) from the over spray, as oils are NOT good for the fish. Though with some common sense precautions, people have done this in their AP systems with no ill effects. You don't need to super soak the leaves or anything anyways. After about 4 day repeat once and then again after another 4 days, and then once more just to make sure. (Since more eggs that have already been laid,  will probably hatch). Get a decent magnifying glass and spot check undersides of some the leaves once in a while.

Good luck. Spider mites a a real PITA...catching them before the webbing appears helps alot. Expect to loose some leaves, as they will drop off at the slightest perturbance, but your plants should make a full comeback, depending...

Oh yeah, DO NOT feel the urge to over do it with the oil in the mix. Anything over 6%-8% tends to burn the plant leaves...So keep the total oils under 5%...

I will run out and get the oils now. I just need to figure out how those percentages work out in measurements that I can actually use. If I am making a 16 oz solution, how many teaspoons of oil and soap. Good thing I studied math in school.

Spider mites are the single biggest pest I have ever fought, and I still fight them. My advice is to pick an arsenal of weapons that work for you, and then alternate through those weapons in a twice per week war. They are easy to kill, virtually impossible to decimate. SM prefer hot, dry conditions. Powder mold, also ever present, prefers cool moist conditions. If you adjust your climate to the middle of the two extremes, both will thrive. Experience talking there. So, don't worry about RH and Temp, IMO.

Weapons with high personal success:

1- oil spray
Vlad's recipe and dosage are spot on. Others work too, like plain old cooking oil and a drop of soap. I use a brand called Organocide from HomeD or most anywhere. A $14 bottle if concentrate will last you forever. It is made from soluble fish oil, smells like fish, and fight a huge number of pests AND molds. Mist ALL surfaces of plants. Mites are everywhere, you will not get them all, but try anyways. Start with the undersides of leaves, tops get wet from mist settling. I don't recommend this more often than once every 2 weeks. Oil plugs plant stoma, and plants will suffer more than mites if overused.
2- neem oil
NOT safe for fish, but if you're careful and clever, you can pull it off. Apply same as #1.
3- worm casting tea
Totally safe for plants and fish, foliar feed while you kill mites! High benificial bacteria count in fresh tea also discourages mold.

Weapons with moderate success
1-other homemade sprays, using various recipes of garlic, cayenne peppers, sugar, lemon juice, and or soap
Straight old water kills and removes a good number of mites, especially if your plant is mobile and you can take it outside and give it a proper shower. Rainstorms are best, followed by a cold wet chilled night outdoors.
DE is also great prevention to a host if baddies, though I can tell you it will not destroy all mites. I have heavily dusted test plants with only DE for weeks, and then inspected the leaves with a glass. Many where shriveled and dead, and plant health was fair, but some mites (20-30%) lived on.
4- burned sulfur
Doesn't kill them; but slows them down, jury still out for how it affects the fish. I have burned sulfur a few times during the winter when PM starts to threat, or heaven forbid, botryitis. No fish issues for me, though I hate to use my experience as a guide for sulfur toxicity
5- high CO2
Apparently, over 10,000 ppm will kill every living creature in a sealed room. If you have this resource and a sealed room with no fish or pets or people, try it. It's the safest of all poisons, IMO, and bugs can't build up a tolerance to it. I intend to do this once my rocket heater is ducted and tested. I figure a heavy pumping of outside air into fish tanks should keep them alive. Cross my fingers

Weapons of low success:
1- Sprays of alcohol, or H2O2.
2- sacrificial plants
I have read many reports of adding spidermite favorites to a greenhouse, with the idea that the mites will attack the candy and leave the rest alone. BS!
3- climate control, increasing humidity and decreasing temp
If you have mites in aquaponics then you already have high humidity. If you go to the extreme, then mold awaits you.
4- beneficial predators
I hate to include these here on the low list, and to be fair I have only tried lady bugs and lace wings. If someone has any evidence to the contrary, please show it. I really want to trust in predators, but here is the problem. Greenhouses aren't natural. All the natural checks to control mites outdoors are short lived in a greenhouse. First off, they are expensive. Second, all the above controls kill predators too. In order for predators to explode in population to knock out the mites, mites must already be infested, and then you have to painfully wait while damage continues, hoping for the best. The predators I'm convinced are the most effective will turn on each other once spidermites are eliminated, which means when their job is done, they're gone too. The only way I can see that they might be worth it is too quarantine the worst of the SM plants, and place your predators with it to build population while your battling the SM in the main room. Then, let the predators go in the main room to seek and destroy any you may have missed. Then treat the room like a lab, to prevent relapse. Screened vents, no pets, and a quick shower for all visitors, and no starter plants or unsterilized media allowed in the room. Takes the fun out of it.

There. That's my $.02. Whatever you decide to do, alternate treatments twice a week for at least two weeks, 3-4 if you can. Then a worm tea soaking once or twice per month should keep the evil at bay

Predators are certainly not going to eliminate your problem overnight but used in the right way they can prevent mites and control an existing infestation. ladybugs are probablythe most useless of all predators agianst mites, they will eat anything but not quickly and you would need literally thousands of them. i have no experience using lacewings. but when you release 25,000 predatory mites into a enclosed area in the right conditions they do work. and its easy to do. they will establish a breeding polpulation and providing there is food and reasonable conditions they will keep working for you.

 if you have had experience of mites in the past but think you have a handle on it then they are really quite good, you can get slow rlease sachets, a mixture of live and eggs, and they hatch over a period of 4 weeks so they are there ready if your spidermites return. prevention is always better than the cure and i find it works best if you have a planned pest prevention programme involving constant restocking of predators and treatment of stock plants before entering the main systems/beds etc.


Thanks for the reply, Ian. I really want to put faith in predators, and it sounds like your experienced. So, mind if I ask a few questions? Good, thanks. Suppose I have a have 2k' GH, with various crops, and I have it under control with some sprays, DE, etc.; but if left unchecked I would have problems with spider mites, aphids, ants, and white fly and some caterpillars. How much of what kind of predators do you recommend? Approx cost? How many re-stocks per year? How do HID lights affect them? Strong oscillating fans? Now, if they're are doing there job, everything's all good, and you get some powder mildew, can you spray any fungicide without nukings the predators? Worm tea?

Sorry to trouble you, it's just that I haven't had the chance to ask a first-hand user of predators, nematodes, etc. Thanks

The day before yesterday while spot checking some pepper leaves (I do this at least twice a weak) I spotted the dreaded things. It was only on one plant, and I only managed to see 5 or 6 of them. Needless to say I sprayed every plant with the oil mix, then with plain water today. And will keep this up for the next couple of weeks. I believe that I caught them early enough as this seems to be key. The earlier you catch them, the 'easier' you can kill them all, in my experience. Noticing you have spider mites only when you notice the webbing is generally pretty bad/hopeless (or breaking out the big guns toxic time)...

These sprays and what not, are OK, if you only have a couple dozen plants, but I have no intention of hand spraying in a 2k+ sq.ft GH come this year, so I too am interested in any ones experiences with any sort of predators. Stocking, re-stocking prevention program. Combinations of predators, when/how/how many to release would all be very helpful information and any shared experience would be greatly appreciated...

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