Leaves that are dry and crunchy at the very top

[thumper9]

I am growing an autoflower (BlackJack) and a feminized Zkittlez and I am 5 weeks into flower. I noticed on two of the plants ( I have 3) that at the very top colas have burnt-like leaves that are crunchy. I thought over watering but I am pretty strict with that. Now I think the light might be too bright (Viparspectra P2000 LED 240 Watts) at 75% and about 18in away from the tallest plant. I am first-time grower so if anybody has any advice I would appreciate it.

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[Phyto]

Not sure if I can pinpoint the issue, the leaves are very dark green so you might want to cut back on the N. Too much N can interfere with the uptake of a couple essential nutrients, Ca being one of them. I doubt it's light burn, but it could be nute burn. Let's see what others say.

 

[thumper9]

Yeah I am so new. I'm just using the foxfarm schedule with the trio. I'm not adding anything else.

 

[RootFarmer]

Hopefully not this.....

 

[Phyto]

I'm thinking deficiency, toxicity, or lockout. Are you using any Calmag?

 

[BearWater]

You might try raising the lights a tad or turning them down a hair and try just water for a few waterings.

I think phyto is on the right track! All of those can be cause by too much light (obviously there can be other variables also)

What medium are you in?

 

[thumper9]

I am using promix mycorrhizae, organic worm castings, organic perlite and 4-4-4. I was supposed to feed them again today but I did not. Pots were not fully dry so I just gave them a little bit of distilled water. Ph55.

 

[Phyto]

I am using promix mycorrhizae, organic worm castings, organic perlite and 4-4-4. I was supposed to feed them again today but I did not. Pots were not fully dry so I just gave them a little bit of distilled water. Ph55.

Unless your tapwater is awful, I would not use distilled water, it has absolutely nothing in it, no Ca, no Mg, no nothing. It's like using R/O water. I'm a bit confused, you said you're using the fox farms trio of nutes, which are synthetic, but you show a picture of a box of 4-4-4 fertilizer that's not FF. If this is an organic grow, any changes you make are going to take a while to show. 5.5 ph is a tad low, I'd shoot more for 6-6.4. If it's synthetic then you definitly want the PH up around 6.2-6.4.

 

[thumper9]

I just saw that picture up there about the mites and that looks like it. I don't give any cowmag.

 

[thumper9]

Unless your tapwater is awful, I would not use distilled water, it has absolutely nothing in it, no Ca, no Mg, no nothing. It's like using R/O water. I'm a bit confused, you said you're using the fox farms trio of nutes, which are synthetic, but you show a picture of a box of 4-4-4 fertilizer that's not FF. If this is an organic grow, any changes you make are going to take a while to show. 5.5 ph is a tad low, I'd shoot more for 6-6.4. If it's synthetic then you definitly want the PH up around 6.2-6.4.

Yeah these are just the things I got off the web but I don't understand the organic synthetic so I'm learning.

 

[Phyto]

Yeah these are just the things I got off the web but I don't understand the organic synthetic so I'm learning.

Here's the difference in a nutshell. In organic grows the microorganisms in the soil break down the more complex molecules of nutrients into a form that the plants can utilize, and are usually dry amendments. In synthetic grows the nutrients are bound to a salt, and when you mix them with water the salt disassociates from the nutrients and the nutrients are immediately available to the plant, no mirorganisms are needed. The upside of synthetic is that the nutrients are immediatley available to the plant, and you can see results quickly, the downsides are the plants need to be fed with every other watering, the PH must be correct, and the salts can eventually build up and cause lockouts, which necessitate flushing the media with fresh water (three times the volume of the pot) to wash out the salts. Organic grows are more forgiving of PH issues, and the feeding schedule is easier.

 

[PlumberSoCal2]

Unless your tapwater is awful, I would not use distilled water, it has absolutely nothing in it, no Ca, no Mg, no nothing. It's like using R/O water. I'm a bit confused, you said you're using the fox farms trio of nutes, which are synthetic, but you show a picture of a box of 4-4-4 fertilizer that's not FF. If this is an organic grow, any changes you make are going to take a while to show. 5.5 ph is a tad low, I'd shoot more for 6-6.4. If it's synthetic then you definitly want the PH up around 6.2-6.4.

I agree. Most tap is near 7pH and 100-250 ppm hardness with most of that calcium. The nutes I use lowers pH to 5.8 and raises hardness to near 800-900 ppm but I am adding calcium and magnesium sulfate (epsom salts)

Mix some up and test it and then give it a try on one plant.

 

[thumper9]

Here's the difference in a nutshell. In organic grows the microorganisms in the soil break down the more complex molecules of nutrients into a form that the plants can utilize, and are usually dry amendments. In synthetic grows the nutrients are bound to a salt, and when you mix them with water the salt disassociates from the nutrients and the nutrients are immediately available to the plant, no mirorganisms are needed. The upside of synthetic is that the nutrients are immediatley available to the plant, and you can see results quickly, the downsides are the plants need to be fed with every other watering, the PH must be correct, and the salts can eventually build up and cause lockouts, which necessitate flushing the media with fresh water (three times the volume of the pot) to wash out the salts. Organic grows are more forgiving of PH issues, and the feeding schedule is easier.

That was well said and now I totally understand that I'm actually using both. I really appreciate your response.

 

[ajpapenfuss]

If u mist ur plants and look close u can c webs if u have mites