Bottom Leaves Look Yellow/Brownish and are Pretty Dry (Pics)

My plants are about 4-5 wks old. I have 9 plants, all under a 1000w hps 18/6 in some homemade soil my grower buddy made (no idea what's in it, but he said there should be enough nutes for 3 wks, and that it drains well). I just started them on big bloom a week and a half ago, have been giving them nutes every other water (usually about every other day between waterings, so every 2-3 days have been giving them nutes). A couple days ago one of the plants had yellowish browning on the bottom leaves and I didn't really think that much of it, but now 3 of the other plants are doing the same thing so I'm getting fairly concerned. 7 of the 9 plants are autoflowering strains, and 2 of them are not. I took pictures of two of the plants. The one that's started budding on top is easy rider by joint dr, the other one is auto assassin. The other two with the problem are also showing buds on top, but the yellowing isn't quite as severe.


I've looked on the internet and throughout rollitup, and I've seen two main conclusions: it either needs more food, or the ph is locking up nutes, at which point you should not feed them and flush them. I have a feeling that, if my problem is one of these, it's most likely the latter, seeing as I have been feeding them for a week and a half. But I have a couple hours before the water I got at the store to flush them isn't ice cold anymore, so I figured I'd ask people with a little more experience. Thanks.


Also, one weird thing I've noticed. I'm not sure if it's related, but it was just kinda weird. For the past week or so, the only one that's put off any scent has been the easy rider. But today, I can barely smell it. I don't really know anything at all about what factors contribute to the smell of a marijuana plant. I just thought it was strange that today it doesn't smell as strong as it did two days ago. At least, I don't think it does. Could just be that my nose is wrong.

Looks like a P deficiency from those dark blotches.

yes this is most likely pH problem, 90% of these problems are. you wrote a lot but you didn't say - have you been adjusting pH to 6.5? If not, yes you should flush them with pH 6.5 and keep watering/feeding with pH 6.5.

Definitely a pH problem. Flush, flush, flush. You'll want to flush with three times the amount of soil you have. 5 gallon pots = 15 gallons of properly pH'd water.

For the most part my water has been around 6.8ish. All the leaves on one of the plants are now light green, much lighter than the other plants. I read that may be a nitrogen deficiency. I have some Mexican bat guano, 10-2-2. Should I try using some of that?

I have been flushing them with straight water for a week or so, they're only 3/4 gallon pots so I shouldn't have had to use too much water.

I say - give them today (or whenever they are dry) a good flush of water with pH slightly lower (say, 6.2 or 6.0) - with 2.25 gl of water, just to be safe.

Then, tomorrow, even though it's still wet - give them water (not too much of it) with a light dosage (say, 1/3 strength) bat guano. See if they pick up from there.

Will do, thank you.