3 Jack Herer Autos about one month above ground, growing in Fox Farm Ocean Forest soil, pots are 2 fabric 5 gal, one plastic 4 gal. Seeds were started in solo cups and transplanted into pots once the leaves were starting to overhang the cup. No feeding thus far, only water.
Light is a Spider Farmer 2000 running @ about 80% for 18 hrs a day. The lighter green plant is maybe 3 days older than the two darker green plants and is the one in the plastic pot. I’ve been pretty careful about proper watering, allowing it to get fairly dry between pretty thorough wetting, watering about once every 3-4 days now, once pots feel light and soil seems dry down as far as I want to stick my finger.
I snapped a couple pics in natural sun light for comparison as well. Aside from the color difference, all plants seem very healthy and vigorous. Is this normal or something that I should try to amend?
1LuckyMF, yes it has drain holes but it’s not in a catch basin full time. I don’t water it until runoff but when I do water I set it on top of a bowl temporarily, just in case. My watering goal is to fully wet the pot without runoff and then allow it to dry until it’s pretty light before watering again, about 3 days currently.
I did water all three to gather a little runoff a couple of days ago to check PH and PPM. Water PH was 7.0, runoff PH was about 5.9 and PPM was between 1,200 and 1,800. Understand that I didn’t water to 20% runoff, just enough to test, maybe 1/4 cup out of each pot.
These plants are growing in Fox Farm Ocean Forest soil, have never been fed and only watered with 7.0 tap. I assume the runoff PH would be in that range if I’d continued to 20% runoff instead of just 1/4 cup, but I didn’t want to wash out the nutrients in the soil unnecessarily. I know a lot of soil growers never worry about runoff PH unless they’re feeding heavily so I figured it was probably fine.
Is a soil pH of 5.8-5.9 something to be concerned with? I know that trying to amend soil pH in a fully rooted pot isn’t exactly straight forward and I know people often do more harm than good trying to adjust it.
It’s getting there, yes. An out of range pH can impact nutrient uptake. Once you get much below 6.0 phosphorous, calcium, and magnesium uptake is compromised.
Best used sparingly and raising the pH slowly so that the plant isn’t shocked by a sudden change in pH or highly alkaline water. Water at a pH of 7.0 to 7.3. I’ve watered at up to 7.8, so low 7s is a conservative way to go about it. Doing so should raise your root zone pH over a few waterings. It may be a struggle to raise pH depending on what is going on. If this is ineffective, then let us know and we’ll go about getting your pH up in a different way.
My tap water that I’ve been watering with is 7.0-7.3 already. I suppose I could mix up a gallon of 3/2/1 which drops the pH and then adjust it back up with this like I used to with straight coco but my runoff ppm was over 1,400 last time so I’m not sure if feeding is the right plan either. I do see some brown spots appearing on a few leaves here and there.
If you have been watering at 7.2 and your runoff pH remains below 6.0, then there are bigger issues going on. We see a bag of Fox Farm soil with pH problems a couple of times per year and you may have gotten one of them.
I would try a flush and see how it goes. Flushes are usually done after feeding for a while after acidic mineral salts build up. In this case it may be effective. Flush until your runoff PPM is <350. This will flush out any acidic mineral salts and usually results in a pH of ~6.5 in Fox Farm soils.
Let us know how it goes. I’ve recommended this a few times when we’ve seen similar instances and I’ve never seen a follow up to confirm that it was effective. The fact that they don’t come back for follow-up advice suggests that it has been effective in the past.
Overwatering isn’t how much you water at one time, it is watering too frequently and not providing the plant’s roots with wet/dry cycles. Just be sure to let the soil dry out before watering again.
Washing out the nutrients is the point of the flush. The objective is to get rid of alkaline mineral salts. It’s okay to feed immediately following a flush, but keep in mind that wet soil won’t absorb nutrients very well. Resume full feeding on the next watering after the soil has dried out.
I appreciate it and think I should go ahead, even though the plant still looks pretty good. Now is a good a time as any since the soil is hydrated. Once I get PPM down below 350 and PH into the mid 6’s should I wait to feed until the next watering in a few days? All I’ve got here for fert right now is Jacks 3/2/1.
Some would argue that it isn’t necessary unless you see symptoms on the plant, which is a legit argument. If it were my plant I would go ahead with it since your pH is < 6.0.
Jacks is a good choice. Intermittent flushes are necessary when using some nutrients. The Fox Farm Trio is an example. It is a vert salty product. Jacks is less salty. I use Jacks and rarely have to flush.
I do think the lighter green is a symptom of a problem because the entire plant isn’t equally lighter green, some branches leaves are a little darker and some a little lighter, it’s not homogeneous like the others. And it didn’t start out that way, when I look at pics from a couple weeks ago it was darker green like the others. That plus a couple leaves yellowing what I consider prematurely (1 month old plant) and i think your advice is solid. I’ll report back either way.
Since you’re familiar with Jacks, do you use it in standard 3/2/1 formula start to finish? This plant is flowering now and it seems like some people use a different feeding schedule for flowering plants but I don’t know how that applies to soil grown.
