??? To much or not enough of fertilizer???

Hello,
this is my first post in this forum. Till now i was fine reading in your forum and I have to say it was very helpful, but now I am at the point where I need some advice from you guys.

My Babies seem to have either a poor appearance or to much of the fertilizer, I am not sure. In my frist grow I gave them to much and pretty much lost half of them. So now I am very careful and I only use the standard HESI sheme as written on it.

Set up:
600W
1,44 qm
5 Plants:
2x Critical Jack
2x Special Queen #1
1x Critical +
on soil (own mix of: 15 % Plagron Bad mix
75 % Plagron light mix
10 % Perliete
with Hesi

Temp 22-28 degree celsius
rh between 45 and 80 depending on day/night

Its my first scrog set up and all vegi long the babies seemed to be perfectly fine. Now after 6 weeks in veg (started from seeds) they seem to miss something.
Now they are in the 5th day of flowering.

It seems to be some dark spot that start at the leaves outside and go to the inside. ALso some leaves seem to have a lighter green on the outside now.
The get the fertilizer 2 times per week accoring to the standar hesi dosis when they get the water..

I added 3 pictures which hopefully help you to see what i am talking about. One picture shows the general set up, the other 2 pictures show the poor appearence.

I think they are missing Potasium (K) but I want to double check with you guys to prevent over fertilization as it happened with the last grow (my first one )

Thanks guys,
Miri

Hi Miri,
Welcome to RUI. First I wanted to mention that nutrient labels/directions are often too high and should be used with care.

I don't see any dark spots not am I seeing any edge lightening from K deficiency. K deficiency is quite unusual unless caused by lockout of nutrients.

I do see some leaves that look like Mg deficiency. But with photos, sometimes the texture of the leaf can make it look like that. In person, are you seeing any leaves that are lightening in a stripped pattern with the leaf veins still darker green? That's most commonly a Mg deficiency which actually is fairly common with ganja. I prefer epsom salts (MgSO4) in fairly low doses to treat it. 1/4 to 1/2 tsp/gallon. tsp is about 5mls.
JD

Thank you JohnDee for helping me out here. I am not sure about the lightening in a stripped pattern with the leaf veins still darker green, I think thats not the problem. I made 3 more pictures which show it better and in real colour. Have a look

Miri,
OK, I see what you're talking about. Whenever I see splotches like that, I always suspect something going on with Ca. Are you using tapwater and is it very hard?
JD

PS I don't know what that edge burn is...but I'm quite sure it isn't K related.

What do you mean by Ca (Calcium?)
Yes I am using tap water and I guess its pretty hard. Well, when I put a gallon of water into a glass I can see how it has many little white particles in there and it takes a few seconds till it sets and turns into a clear and see throu water.

Miri,
Yes Calcium. The water you use to grow plants is very important. Much of the common minerals in hardwater are Ca based. And most nutrients also include calcium...so it's easy to overdo it. Are your ice cubes super cloudy?

Ideally it would be nice to know the ph and EC of your tap water. Do you have any grow buddies? Anyway to get your water tested? Can you look online and see if your community posts it's annual drinking water testing results?
JD

yes my ice cubes tend to be white. Not super cloudy but more cloudy than clear.
EC and PH testing is not possible for me. I am at the "end of the world" location and its pretty hard to get these testers here. The local "community" does not post anything.

I guess I will have to get through this one without EC ph testing. But the water has many white things in it.

M,
About 10 years ago I had moved to a new community and started having grow issues somewhat like that. The brown spots mostly. And it turned out to be my water which was very hard. If there's any way you can get some sort of water filter, or bottled water...that may help. If you can get 'purified" water and maybe mix it 50/50 with your tap...that might be enough. Also I wouldn't increase nute dosage for awhile. I'm thinking you may be at the top range for right now. That opinion is based on a few other slightly burned areas on leaves.
Good luck,
JD

I was thinking too much Ca too, but another theory is that you spilled nutrient solution on the leaves or 2 leaves were touching and sweated.

If your water really does have too much Ca (often it's hard to tell what's in high ppm tap), you can use some nitric acid in place of whatever provides calcium nitrate.

Thank you JD and Churchhaze for the advices here I could get these PH teststripes from a drugstore (meant to be used for urine testing). according to these stripes the tap water has a PH of 7. growing on soil that should be fine or?
I also got some destilled water. I will mix that one 50/50 with the tap water. Should add some apple vinigar to probably change the EC?

miri,
Ideal soil is around 6.5 ph. EC refers to an electrical current measurement to measure nutrient mix strength. More necessary with hydro.

If you want to mess with ph correcting, it wouldn't hurt anything...but 7 is fine with soil.
JD

Ok, I will give them a 50/50 mix of destilled and tap water with 3 ml of apple vinigar per liter and the normal dosis of HESI for flower. Lets hope its not going to hurt them

Mira,
On the vinegar...always measure the ph when using that. You don't just use a measured amount regularly like a nutrient. Mix the nutrients with the water and then check. Then...and only if it needs it (obviously), correct with vinegar.
Good luck,
JD

Ok, I measured it and using 50/50 destilled/tap water the ph was on 6,5. So no vinigar. Lets see how it goes. I gave them only half a liter each, thought its better to give them every 2-3 days a little instead of only 2 times per week a lot.

miri,
Yes that sounds good. Make sure you let them dry in between rather then just going on a schedule.

Nutrient burn almost always shows first on the leaf tips, so that's one thing to watch for if you change the nute dosage up. And chlorosis (yellowing) from not enough nutrients occurs on older leaves. That's how you learn to "read" the plant is by looking for those kind of things.
JD

PS: It's always best to not add nutrients when super dry...which might seem contrary to above advice. When adding nutrients, first water with a small amount of plain water...then add nutrients. That's so the dry plant doesn't suck up the nute solution too fast...minimizes burn risk.

calmag? Maybe... idk

yeah thank you, I try to let them dry before adding water. I am afraid of mold if i keep them wet all the time. Just came to my mind maybe thats also important, I always had the soil a little dry and i have them in BIG 9 gallon (38 liter) pots. Maybe it turned to be to salty??? what do you think JD?

Miri,
That's a big pot. You must be planning in growing them to be huge. With large pots and smaller plants...they don't use up the moisture fast enough and pots stay wet for a long time. Best thing is to do what you're doing which is to just water around the plant.

And yes you do run a risk of accumulating nutrient salts...and perhaps they should be flushed or at least watered to significant runoff perhaps monthly. I really don't know. Never grown in such large pots...and now I do mostly hydro.

You should transplant up in stages. And most guys manage large plants quite nicely in 5 gallon pots. But hey, that's what you have.
JD

JD is giving good advice, as usual. Another way to tell if you have hard water if you don't have a testing device is to look for rings in your toilet or shower heads that are clogging up with mineral deposits.

Your potting soil is not very nutrient rich so you are probably doing well to give them the directed nutrient levels, but at those levels it is good practice to flush every couple months. If you upgrade your soil on a future grow, keep in mind that you will want to decrease your nutrient levels. Highly recommend you order a EC/ppm testing device, even if you have to pay a little more for shipping. If you plant to keep growing, they are worth it. Keep good notes on everything you do and you will shorten the learning curve.

Keep up the good work!

For your waters EC, the local waterworks can usually answer it easily. Send them an email or give them a call. At least where I live they always monitor it and I can actually just visit their website, insert my address and I'll get the PH and EC levels. Tested the PH myself with both strips and two kinds of PH paper, all three showing the same result with little variety