A Friends Grow Problem

[F420]

Hi,

 

Although I dont have a grow myself. I am watching a friend grow his and learning all I can before I bite the bullet and start a grow.

 

Now I checked on his grow this morning and found some weird shit, his top leafs are curling up bad almost looking like a tube kind of, it doesnt appear to be a nutrient problem as hes only running at approx 1.2 EC, and his Ph is 6.2, his nutes are well oxygenated by a airstone.

 

It cant be heat as he actually overkills the ventilation with 2x 250mm hydroponic fans.

 

The light is approx 2 feet away from the tips.

 

heres a leaf-

[F420]

This is another leaf that is showing slight yellowing in the leaf margins, it also has a couple of spots that look like rust?

 

there is no signs of mites, or scarid fly or anything like that.

the ONLY thing he done differently is he used a half strenght monster grow as an additive??

 

I have suggested that he dump his nute mix and use straight ph adjusted water for 3 days, but he said what if its a dificiency? taking ALL nutes away will make it worst.

 

what do you think?

Edited March 9, 2004 by Ferenge420

[F420]

bigger pic of leaf 1,

 

room temps are about 28 deg, and he flushes for 2 days everytime he changed the nutes.

Edited March 9, 2004 by Ferenge420

[Luke Skywalker]

If this is a hydro sys, then I'd drop the ph levels to about 5.5. Some others grow perfectly well at these levels, I tend to develop problems myself outside that level.

 

He doesn't need to flush for two days. Just tell him to put though several watering cans of fresh, ph adjusted water through the pots at flush/reformulate time, until the runoff coming out of the pots is the same as the water going in. You can test this with a truncheon, which I assume he has.

 

It could be a nutrient lacking prob too, early signs. Try bumping it up a point or two on the truncheon and see how it reacts, as well as the things I've outlined above.

 

That said, I'm sure many others will give you much different advice. Pick the ones which sound right to ya.

[gunjaponic]

I am in no way an expereiced grower, but I have found that the leaves on my plants curl a bit if the light is too close.

 

And I'm with Luke on the PH as well.

[jaikai]

first thought would be light/burning. beyond that youd be thinking nute, hard to pick like that too...cant know the overall conditions, myself, id flush them and wait a couple days...

 

JAIKAI

[F420]

update-

 

I passed this information on to him and he has dropped the ph to 5.5 well actually he is using a liquid tester and we find it hard to get it perfect but it was a piss looking colour and now its got a very slight redish tint to it.

 

We have lifted the light another foot so its about 3 feet away now.

We changed the nutes and put straight tap water through it for approx 30 mins constant, we had fresh water coming in the top from a hose and sent all the water coming out straight on to his grass outside, We then refilled the res with ph adjusted approx 5.5 and will leave this for 2 days. Then we plan to refill with more ph adjusted water and A+B to approx 2.0 EC (yes he has a truncheon).

 

No change yet but im sure your all right, so we will just sit back and watch until saturday.

 

Thanks for the advice, A second opinon is ALWAYS worth its weight in bud.

 

[Luke Skywalker]

You need to ph adjust your flushing water to 5.5 as well, or you'll be setting the media at a higher ph level. What's the pH of your tap water?

 

Don't jump from1.2 to 2.0. Just go up slowly, a couple of points at a time, maybe .2 each week or so. If you overdo it the plants'll scream, and that kinda damage can't be undone. Tis a far, far better thing to underfert than over.

[Tom]

What wattage is the light? I would say that was the reason for the curling, the temperature at leaf level would be much higher than it is on the wall where the thermometer is. To fix this you can either get a bit carried away and buy one of those thermometers with a thermocouple attached so that you can take temperature readings at tip levels or you can use this method of setting your light height: To set the light to grow height, start at a safe distance above the plants (approx 45cm for 400w, 90cm for 600w, 1200cm for 1000w), hold your hand palm down level with the top of the plant for a few minutes. If it feels too hot on the back of your hand the light is too close, if cool then it's too far away. If it's pleasantly warm and it feels as if you could hold your hand there all day then it's OK.

 

This is another leaf that is showing slight yellowing in the leaf margins, it also has a couple of spots that look like rust?

The yellowing would be the due to a poor nutrient take-up due to the higher ph, the "rust" would be directly due to the ph being too high, a ph of 6.2 is mostly seen in run-to-waste rather than recirculating systems.

[indooraussie]

magnesium deficiancy.

found this for you

 

Magnesium (Mg)

Magnesium is a component of the chlorophyll molecule and serves as a cofactor in most enzymes.

Magnesium (Mg) deficiency:

Magnesium deficiency will exhibit a yellowing (which may turn brown) and interveinal chlorosis beginning in the older leaves. The older leaves will be the first to develop interveinal chlorosis. Starting at leaf margin or tip and progressing inward between the veins. Notice how the veins remain somewhat green though as can be seen in figure 15.

Notice how in figure 16 and 17 the leaves curl upwards like they're praying? They're praying for Mg! The tips may also twist.

This can be quickly resolved by watering with 1 tablespoon Epsom salts/gallon of water. Until you can correct nutrient lockout, try foliar feeding. That way the plants get all the nitrogen and Mg they need. The plants can be foliar feed at ½ teaspoon/quart of Epsom salts (first powdered and dissolved in some hot water). When mixing up soil, use 2 teaspoon dolomite lime per gallon of soil.

If the starting water is above 200 ppm, that is pretty hard water, that will lock out mg with all of the calcium in the water. Either add a 1/4 teaspoon per gallon of epsom salts or lime (both will effectively reduce the lockout or invest into a reverse osmosis water filter.

Mg can get locked-up by too much Ca, Cl or ammonium nitrogen. Don't overdo Mg or you'll lock up other nutrients.

 

 

 

Figure 15

 

 

Figure 16

 

 

Figure 17

 

 

Magnesium (Mg) Toxicity:

Magnesium toxicity is rare and not generally exhibited visibly. Extreme high levels will antagonize other ions in the nutrient solution.

 

sorry couldnt get pictures to come up