Slow growth and leaf problems - autoflowers

[PrinsesS]

They should go through complete wet dry cycles. (I can't tell from your comment if you've been doing daily watering.).

I was watering until I started to see run-off then would stop, and it would take a week when they were small to dry out. These days, some of the larger ones may need water every 5 days or so, but they can typically last the week and I'll do everything at once.

I use 60% Pro-Mix HP, 20% Kellogg Patio Plus (potting mix) and 20% Perlite. The Pro-Mix already has 30-40% perlite. So, my stuff is up there close to 40-50%.

What soil are you using? I assumed it's Fox Farms (which one?).

With the older ones, half the pots are sh*tty miracle gro potting soil, and the other half miracle gro organic potting soil with extra fungus gnats. The younger ones, including the seedling in the photo are in a 50% Pro-Mix, 25% Perlite, 25% Vermiculite mixture. The ratios varied between pots in the new ones, trying more perlite in some than others.

84 seems high inside the soil. That's starting to push it, I think. I'm in a hot climate and in the summer my plants struggle at the 84-86 range. I've never measured the temperature in the soil. But, I don't see how it would be hotter than the ambient air unless there's some kind of activity happening in there.

I have to check the manual to see if the meter means ambient temperature, or soil temperature, and to see if I can calibrate the PH as Orbo suggested. I have a feeling its ambient because 84'F would be the temp the grow tent is heating my bedroom to since it's exhausting into there. Inside the grow tent that meter shows 77'F so I think it's ambient.

What is the PPMs of your tap water? (You can buy a $20 TDS/PPM meter on Amazon. I use the HM EZ-TDS.). If it's too high that could be causing a problem, loading up the soil with non-nutritious stuff, competing with the nutrients. I had that problem when I started. My water's PPM is 600-800. I mix it with RO filtered water to get a starting point of 150ppm.

Chlorine could be a concern using 100% tap. There's not a lot in tap water compared to the unsanitary nature of soil. Soil should win every time. But, I would put a pinch of sugar in the water the night before just to promote some bacterial action and exhaust the sanitizer. Then mix your nutes. (Let it sit too long and it will get gunky.).

If you're in the US you can search for your water provider's required "annual water quality report." That will tell you some things.

No idea....I'll have to look into this.

Thanks for the advice!

 

[PrinsesS]

Just to compare against my digital ph tester, my chemical tester shows my tap water is about 7.0 as well....sooooo it might be accurate, but i'll still look into calibrating it.

 

[az2000]

I was watering until I started to see run-off then would stop, and it would take a week when they were small to dry out. These days, some of the larger ones may need water every 5 days or so, but they can typically last the week and I'll do everything at once.

It does take longer when the plant hasn't yet grown into the container. But, that sounds a little long. I like 2-3 days when they've filled the container. 4-5 days when they've been transplanted and haven't grown into it yet.

I wouldn't use vermiculite. That retains moisture. (If you were under HID lights it would be beneficial to slow how fast the soil dries under the radiant heat.).

The MG potting soil will probably cause you problems. It's pretty high in nutrients. It should burn young plants and interfere with your ongoing delivery of nutrients. MG organic isn't as bad. But, I like having very little. For example, I would mix those with your Pro-Mix (and perlite).

One thing to keep in mind about your use of Pro-Mix and perlite (by themselves) is that that's considered soilless and has a different ph range. It's between hydro and soil. When I did it, I did 5.8 to 6.0 in veg, 6.0-6.2 in flower.

I think phing soil is pointless as long as you're not using boutique multi-bottle "lineups" with calmag, etc. If the soil is amended with dolomite, it shouldn't be necessary. It should be simple. But, in soilless, you'll probably need to ph that. I dont' think it has the buffering strength that soil would (for example, if you mixed your potting mix with Pro-Mix, and made it more like soil the way I do.).

If you can dial in a light soil and get away from calmag and unnecessary things, you probably won't have to use a ph meter. (I assume we're talking about a ph pen, not your soil probe.) Pens are a maintenance headache: storage solution, probe cleaning solution, calibration. I'm glad to be done with that. Soil probes aren't usually very accurate. Yours might be better than those $10 probes sold at the store.

If I were you, google for that annual water quality report (if you're in the US). Otherwise, call your city and ask the water department about it. A TDS meter is helpful to measure your runoff to see if you're getting salt buildup. It's good to have one. I'd suspect your water right now. It's common for water to be higher than desireable. If you get mineral deposits in the shower, etc., you're probably too high.

 

[az2000]

BTW: This is the EcoSmart Home Pest Control product I mentioned which seems quite effective at keeping the gnats away. It's just an irratent. I spritz the soil and around the base of the container. I bet this is all you'd need (if the peroxide isn't working. The problem with peroxide is that it sterilizes the soil which isn't good.). I wouldn't spray it on the plant. It's pretty strong. And, I wouldn't spray the soil of a seedling (I think I scalded a seedling just by spraying 2-3" away from it.).

I saw your post that you're not using a ph pen (so, ignore everything I said.).

 

[PrinsesS]

Mg lockout calcium, iron, and zink, plus ur heat issue, and infestation of gnats, maybe they are eating your roots, maybe is root rot, maybe its too hot in there. Maybe its a bad combo of all of the above. GL

I'm starting to think you might be pretty dead on. I read the following article and it does seem to match mg, calcium, potassium, and zinc deficiencies or lockout, with maybe a small iron problem as well (might just be zinc): http://gr0wing.blogspot.ca/2012/05/marijuana-problems-symptoms-how-to.html

I wonder if the past flush, added h2o2, and my weekly watering of plain water stripped the soil of essential nutrients

I took a couple of the older plants and flushed them 4x with 2L of PH adjusted water (6.0 ph), then flushed twice with a light nutrient mix of Grow Big, Big Bloom, High Brix Molasses, CalMg, and a teeny-tiny pinch of Cha Ching (like 1/16th tsp to balance out the P/K since I don't have any 20/20/20 around). The plants were obviously showing signs of being overwatered after but this morning after sitting in their dark cycle, they're standing at attention and looking jacked like the last time I gave them a nute kick. I wouldn't have done the above except the leaves just dont have the dark green lustre I'm used to seeing. Instead they felt and looked light green, soft, kind of flimsy as they would if they were underwatered or experiencing root-shock.

I plan to monitor these 2 plants over the next few days to see if any nute burn occurs but if they get better, I'm going to do the same treatment to the rest.

 

[tropicalcannabispatient]

Im glad they are recovering, let them dry up now, then i will do 1/8 grow big 1/8 big bloom, 1 teaspoon of epson salt, 1teaspon calmag, 1 teaspoon molasses. They will recover. GL

 

[PrinsesS]

Hi,

I just wanted to give an update in case it helps someone having similar issues. Here's what I eventually found out was wrong:

1. All of the plants were over-watered. Some by a bit, some by a lot (more on that later). Once the larger plants dried out, they were beaming with joy with leaves looking straight as an arrow.

2. The larger plants were lacking nutrients, and I'm going to assume aren't autoflowers (almost 45 days now and still no signs of sex). I wasn't feeding them because this is what a lot of guides suggest. I'm going to say, give the plant what its telling you it needs even if some guy on the innerwebs says otherwise. My older plants are a deep rich green and look great now after a full dose of every-day 20/20/20 nutes.

3. BTK doesn't kill fungus gnats, but BTI does. Once I purchased the correct strain and applied a small dose to each plant, my fungus gnat issue was wiped out immediately.

4. I'm fairly certain the smaller plants were all suffering nutrient issues due to overwatering. What gave me the clue was when I started to introduce some 2L bottle planters, and saw some new seedlings looking the same after a couple of weeks. I picked up one of the bottles and saw it was really moist at the bottom with no roots in sight. I figured the same was likely happening with the larger pots, so I've concluded that whoever says to transplant autoflowering seeds from germination into their final pots from day 1, should warn you not to water the entire pot after. Instead, just water the seedling and a few inches around it. My initial saturation of the whole pot caused 90% of the soil to just sit there, wet, and compact over time as well. As the plants grow larger after 30 to 45 days, this doesn't become as much of an issue.

thanks

 

[tropicalcannabispatient]

Any updates op?