Problems at 4 weeks - Yellow leaves

[Bigal07]

Hi all,

New to this and have a theoretical problem with a grow. 4 weeks since the seed was planted and up until now been healthy looking, but now the bottom leaves are going yellow and dying. Where is it going wrong?

Conditions:
600w HPS lamp
Miracle Gro fertilized multi-purpose soil

Any advice much appreciated.

[bluesteve]

First, at 4 weeks, it may just be time for the very first leaves to die out, but not usually. You need to tell us what kind of soil you're using. Do you know it's ph? If not, you need to. At 4 weeks, in a pot that small, it could be running out of nutrients, particularly, nitrogen, though this may not be the case. Get a good all around fertilizer with NPK & all necessary micro nutrients, that is approved for foliar feeding, and give her a spray to both sides of the leaves when the room temp is below 80 degrees, and, following the manufacturer's guidelines, give some to the soil, too, but, make sure you're using a water soluble fert. Are you leaving any windows opened that could be allowing pests, like the six spotted leaf hopper, into your house? It's kind of hard to diagnose these things from a distance, but the foliar spray with a complete fert should stop the problem, unless it's insect related. But, if the soil's ph is off, it'll return.

[bluesteve]

This puts a new spin on things, if the soil you're using is the Miracle Grow that is supposed to retain moisture, I transplanted a 4 foot 6 inch plant into that soil last year, and it stopped growing and wasn't worth smoking at harvest time. Not sure that is definitely your problem, but I'd be suspicious of it. With adequate nutrients and 600 watts of light, she should be quite a bit bigger already, and have some bottom branches started. If you'd like to know one of the best soils I've ever used, try Masters' Pride Professional Potting Soil. Not many people are hep to it yet, and it isn't found in many 'grow stores', but lots of regular nurseries carry it. It has all the guanos, chicken manure, and other organic nutrient sources, and it already has Mycorrhizae in it. As soon as you open the bag and get the smell of it, you know it's good. I used to use Fox Farms Ocean Forrest, but this is far better. Just don't buy a bag from the top of a pallet that has been sitting in the sun. I grew plants to 3 1/2 feet with it, before they needed any further ferts.

[Rusty Trichome]

I've seen much worse. Doesn't look like anything terminal.

Ditch the foil. With a 600 watter, heat isn't something you'll want to retain unless it's winter. The reflected light from the foil is negligible, and the foil restricts airflow to the roots.

I'd start thinking about transplanting into a larger pot.

A lot of folks that use MG soils use extra perlite or vermiculite to lighten the soil. This helps prevent the soil from retaining too much moisture. Consistently saturated soil is a harsh enviornment for cannabis. It prefers a wet/dry cycle. (don't overwater)

Since you're using MG soil, once you transplant...don't use nutrients for a couple or few weeks, and then only half-doses till you see their reaction. Are you giving any additional nutrients or additives?

Start thinking about what nutrients you'll want to use in the flowering stage.

[Bigal07]

Thanks for the help! Ive repotted to a 17ltr pot and got rid of the foil. Not using any nutrients just now as the MG soil had stuff in it n im scared of nute burn! ill keep a close eye on it and see how it responds to the bigger pot. Will update in a few days. Cheers again!! :)