VerdantGreen's Quarters - 187 watt LED - Organic Modular ScrOG

[ixnay007]

I would rethink how much of a problem fungus gnats are. They are taken very seriously in commercial horticultural operations. The larvae are the most damaging stage of the pest as they feed on the roots, allowing your roots to be infected with root pathogens that they usually have along for the ride.

Now its not to say you still can't grow some beautiful healthy plants with some fungus gnats in your garden, but they can spread out of control very quickly if not taken seriously. And having buds full of gnats is not a pretty thing.

Yeah, the larvae will eat your roots, but only when they don't have anything else to munch on. If you've got a soil full of compost and fungus, they're not going to be too interested. Toss some DE and neem flour into your soil mix, and they won't end up being much more than an afterthought.

Do you have any DE Verdant? A layer of that between your bark and the soil would help a lot, as the adults would have a very hard time emerging from the soil to mate.

 

[ixnay007]

hey ixnay, i would agree mulching is a good idea in general, but i think in an indoor grow with no worms in the soil it's benefits are more limited and have to be weighed up against the drawbacks.
living mulch, i love the organic fanatics but i personally think that living mulch in an indoor grow is more about striving for best organic practice/box ticking than actually providing any material benefit. in my grow virtually no light penetrates the canopy so i dont think it would work and i also think it provides a habitat for potential pests (as well as beneficials i guess). i know mad l said he left gaps in his canopy to allow the living mulch to thrive and imo that is kind of putting the cart before the horse... but its good that people are trying these things.

dave - i agree with you about the gnats.. i dont worry about seeing one or two but my bark much seemed to be teeming with them at times. by far the best way to control them that ive found is letting the top layer of soil dry out properly between watering and mulch does stop this happening.

Maybe so, but I think the positives you get from keeping the moisture levels up in the soil are more valuable than the negatives from things like fungus gnats. There are plenty of solutions (organic even) to them, drenches being among them.


I think living mulch makes more sense if you're doing no till soil, because the web of roots they send down makes for more structure in the soil functioning as a wick system, and a soil conditioner. Otherwise, I think you're right, if you are only re-using the soil, it doesn't make much sense.

 

[VerdantGreen]

mellow yellow - yep, especially today

2000pm - obviously any perceptions about quality are somewhat subjective... but i would say that the smoke is more 'creamy' and has more flavors - perhaps because less terpenes are lost with LED. also, if anything, the smoke is more potent. ive run the mmg many times and the last couple ive been a bit disappointed. this time im very happy, plus a couple of other people who had a go on it commented about it too.
the UV tubes will probably go back in for the next run but i wanted to run the light on it's own first time round.

hey ixnay, i do use some DE on the soil surface and some bacillus type stuff too, both help, but i find that letting the soil dry out a bit inbetween waterings has the biggest influence. as for the extra water being more beneficial than the problem of a few gnats - perhaps thats true, but i always see air content in the soil as being inversely proportional to water content so a degree of wet and dry cycle seems to make the plants grow well... interesting what you say about what he gnat larvae feed on, if thats true then you are right they shouldnt be a problem.

----

right, we are coming up to 12 weeks and all the last 3 plants were chopped today.
here we have the Chem D - which probably would have been chopped a week ago if i had been able - but today was my first chance. finished pretty ugly but nice to see it fade out so well which is sometimes harder to achieve under LED
looks like i have plenty of seeds too.
chemd x bubba and chemd x shark

nug

 

[VerdantGreen]

C4D - couple of mites have moved in on this one in the last week or two, but nothing much

and a trimmed nug

 

[VerdantGreen]

lastly the sharksbreath

be back in a week or so with the final weights.... and the next round
VG

 

[flubnutz]

this is like when i was hooked on "east enders" ... i can't wait for the finale

VG thanks for a great thread as usual. tell me, do you think you could have gone up one more notch in the light, into the, what is it, 189X-PRO, or do think that would be overkill, to the point of being detrimental to the plants?

thanks again!

 

[Dave Coulier]

Yeah, the larvae will eat your roots, but only when they don't have anything else to munch on. If you've got a soil full of compost and fungus, they're not going to be too interested. Toss some DE and neem flour into your soil mix, and they won't end up being much more than an afterthought.

Do you have any DE Verdant? A layer of that between your bark and the soil would help a lot, as the adults would have a very hard time emerging from the soil to mate.

Ive heard that argument a few times before, and IMO its just something someone said online and it caught on and is now the 'truth'. In fact it likely will cause more problems by using compost.

Fungus Gnats just love organic soils, and will thrive in them, so I wouldn't be so quick to give them an extra food source without proper means to eradicate them.

The larvae are first going to target your roots, and yes they will get infected with root pathogens. Ive seen this occur in my own garden when fungus gnat populations become too high.

As for DE, dont forget the fungus gnats will find a way into your soil. They will crawl in through drain holes at the bottom and make their home still. Ive tried topdressing with sand, and perlite before, and they were useless. I never tried DE, but there are better methods for controlling them. I use liquid BT with good results but not 100% kill rate, but mosquito dunks have provided the best results for me. Im thinking of buying some beneficial nematodes and give them a whirl.

If anyone wants to learn more about fungus gnats, they can check out this greenhouse grower link. Its a video. Turn down your volume at first.

Here is another link discussing fungus gnats and how to combat them.

 

[heady blunts]

wooo they all look very delicious VG!

 

[ixnay007]

Ive heard that argument a few times before, and IMO its just something someone said online and it caught on and is now the 'truth'. In fact it likely will cause more problems by using compost.

Fungus Gnats just love organic soils, and will thrive in them, so I wouldn't be so quick to give them an extra food source without proper means to eradicate them.

Of course fungus gnats love organic soil, they're part of the soil web, on the turning dead plant material into food for bacteria side.

The larvae are first going to target your roots, and yes they will get infected with root pathogens. Ive seen this occur in my own garden when fungus gnat populations become too high.

Yes, if the populations become too high, they'll end up munching on your roots, but if they're just there in normal numbers, they'll chose to eat dead plant material and fungi first.

As for DE, dont forget the fungus gnats will find a way into your soil. They will crawl in through drain holes at the bottom and make their home still. Ive tried topdressing with sand, and perlite before, and they were useless. I never tried DE, but there are better methods for controlling them. I use liquid BT with good results but not 100% kill rate, but mosquito dunks have provided the best results for me. Im thinking of buying some beneficial nematodes and give them a whirl.

DE is better, it is physically destructive to them (death by a thousand cuts), as for the holes in the bottom of your pots, leave a layer of DE in your trays.

There are also predatory mites, if you grow organically and recycle your soil, either the Hypoaspis mites or the nematodes will do well as they're a long term solution and will breed and continue to keep the population of "harmful" insects well under control.

If anyone wants to learn more about fungus gnats, they can check out this greenhouse grower link. Its a video. Turn down your volume at first.

Here is another link discussing fungus gnats and how to combat them.

I prefer this one:

http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7448.html

 

[ixnay007]

hey ixnay, i do use some DE on the soil surface and some bacillus type stuff too, both help, but i find that letting the soil dry out a bit inbetween waterings has the biggest influence. as for the extra water being more beneficial than the problem of a few gnats - perhaps thats true, but i always see air content in the soil as being inversely proportional to water content so a degree of wet and dry cycle seems to make the plants grow well... interesting what you say about what he gnat larvae feed on, if thats true then you are right they shouldnt be a problem.

As everyone here has stated, it's when the populations explode that they end up munching on roots (or they eat enough roots to cause damage you can see). I was thinking, you're using the molar clay as a perlite replacement, correct? It should be fairly good at maintaining moisture in the soil, while at the same time keeping humidity at levels which probably are less conducive to gnat reproduction... maybe upping the amount of molar clay might reduce the humidity as it sequesters the water inside.

BTW, drying out may reduce the FG population, but it does equal damage to the microherd and the plant itself isn't usually thrilled.

 

[paulo73]

Congrats on the harvest VD.
Thanks Dave and Ixnay007 for the input on the gnats.

 

[VerdantGreen]

flubnuts, i quite fancied the 189xpro but i felt it was a bit too much height wise as the cab has very limited height and you probably need to use that lamp at 18-24" above the tops, and tbh even this 126x pro has to be used with too much gap between canopy and light for my cab. im using at about 15" which is the most height i have to spare but it could still do with a few more inches gap for the footprint to spread to the corners. what i'm realising is that the extra gap needed is likely to cost me some yield because normally i have 6-12" of canopy height above the screen and in the last grow i kept it down to less than 6".
basically im very happy with this light but in an ideal world, 2 of the 126X (1w) models side by side would work much better in my space because i can then have the plants much closer to the light and go back to a taller canopy. there is a possibility that i will be able to sell this light on and if i can i will probably splash on the two 126X models as i think that would be even better.
also the 189Xpro is square and my cab is rectangular and a bit too small for it. i reckon 30-36" square would be prefect for that unit as long as you have enough height.

dave and ixnay - interesting stuff on the gnats, i used perlite for this last run but am trying calcined clay again in a new, hopefully recycleable mix this time (more about that later).
the one thing about DE afaik is that it only really works well when it's dry so used on the soil surface you have to allow the surface to dry anyway for it to be effective.
im thinking if bringing in some predators this run - perhaps these?
http://www.harrodhorticultural.com/HarrodSite/product/Fungus_Fly/GPC-034.htm
the thing is that DE will likely harm these too so i'm going to stop using it this run and try the predators. i may try and catch some rove beatles too.
about the wet/dry cycle - it would better be described as a wet/damp cycle... i dont let the soil dry out to the point of the plant being stressed or the soil being actually dry (except the top few centimeters) ive read that it doesnt help the plants but i have to say that from my own observations the plants seem to love it. the most gnats i saw in my grow this time was after i'd been away and the plants had been standing on capillary matiing as an auto water... kept them consistantly wetter and sure enough there was a whole cloud of gnats when i got back.
lastly, another effective remedy for gnats is the old bowl of fruit juice/something sweet as they drown in this in quite large numbers!

heady - thanks for stopping by

VG

 

[GrowbagUK]

I added some neem seed meal to my soil mix just lately and there are definitely less/almost no fungus gnats about. I'm using airpots which they normally love so it seems I am either lucky to not have any invaders or the neem meal is having the desired effect.

 

[VerdantGreen]

yeah i would defo use neem seed meal if you could get it in the UK... but you cant!

hold on... are you from the UK growbag??? where did you get the neem seed meal????

 

[PetFlora]

You can also try an IR bulb for ~ one hour immediately after lights out. Also excellent for tric production

 

[ixnay007]

You could also just suck it up and enjoy your fungus gnats like a man!

 

[nickman]

yeah the DE needs to dry to work well so it kinda sucks cause it only works for a day or two until u water the plants again, then i would just have to put it back on top the soil again ...

it became a real pain in the ass ...

 

[GP73LPC]

hey VG, looking forward to your smoke and total yield report...

another fantastic grow !!!

 

[heady blunts]

if you can source neem seed meal it makes a big diff w the fungus gnats. between that and smart pots, which I feel distribute moisture more evenly than other pots and therefore rarely have that soggy bottom layer the gnats love, I don't see them anymore.

 

[GrowbagUK]

Sent you a PM. If it's OK to put up the link I will post here.