Hello people! I'm a noob growing my 2nd plant (1st time indoors), and I'm having some problems which I fail to identify. I would appreciate any tips, advice or opinions.
TLDR: https://imgur.com/a/C9WFHQm (scroll down for more pics)
34 days ago I planted an autoflower seed (silver haze auto) in generic gardening soil I had laying around, which I mixed with around 10% lava rock which I use for my succulents (I thought it would help with for aeration). I sterilized the mix in the oven as I had some problems with fungus growing other types of plants in the past.
Mistake 1: I over saturated the soil with water before adding the seed as I didn't know any better at the time. The seed sprouted 3 days later, so the plant is 31 days old now.
At day 9, I saw the first problem: leafs were curling inwards and seemed very dry (https://i.imgur.com/YMeodYf.jpg). After asking around for advice, I believe this was due to a combination of factors: lights too close (I use LEDs, at the time I was using 2 x 13 W 1500 lumen 2700k phillips bulbs, as in this video https://www.youtube.com/watch?v=XnIzB_8knLU,at 10cm from the plant) + low rh (~40%) + very strong ventilation. I turned off the ventilation, lifted the lights, got a humidifier and everything got a bit better over the next days (here is the plant at day 11: https://i.imgur.com/wBsIS5g.jpg).
At day 13, the plant started showing yellow / brownish tips on the branches, which was surprising as I hadn't started yet feeding. I got a TDS meter and measured my tap water, turns out it's very hard, around 400 ppm, with a ph of ~8. From this point I switched to distilled water, to which I add 1 ml of plant magic calmag per liter, which brings the ppm at ~200.
Mistake 2: I went overboard with the humidifier, leaving it on all the time for days, to the point that the leaves were constantly wet. Around day 16, this (or at least I think this is the reason) caused the new growth to claw and the lower leaves to show rapidly yellowing and browning, showing deficiencies. From what I read, too much humidity in the air prevents the water flow from the roots up into the plant, so no nutrients are available, that's my reasoning for concluding yellowing + browning were deficiencies.
I removed the humidifier, got a new rh probe as the old one was showing 60% even though the leaves were soaked and kept going. Even though the plant looked bad and it never fully recovered, it got better and kept growing.
I started feeding at day 21 with 1 ml of 7-3-6 fertilizer per liter of distilled water, in addition to the 1ml of calmag, bringing the total ppm at ~350.
I water by weighing the pot every day: I waited until what I thought was completely dry, wrote down the weight, and wait until it reaches that again to water. Typically for me that is ~1.9kg dry, then I water until I have decent run-off (~1l of water, pot is 6l), I wait a few minutes, then weigh again and it's typically ~2.3kg. I used to water once a week in weeks 2 and 3, lately I'm watering ~ every 3 days. I also noticed that when the pot is ~1.9kg the plant droops a lot and it takes it ~10-12h after watering to perk its leaves back to normal. I also have a 3 way meter measuring light / soil ph / soil moisture which I use to double check the moisture level before watering, and it's almost all the way to dry. I am adding all these details because to me the symptoms look like overwatering and I am very careful not to do it, but it's possible I still do.
I also measure the run off ph, which is 6.5, the same as the feed, and the TDS, which is ~400 ppm, a bit more than the 350 ppm feed. From what I read, this could indicate some build-up in the soil.
Light schedule is 20 / 4, I grow in a PC case which I converted and use 6 led bulbs like in the video above which should give ~750 par. The bottom of the case is raised and has holes for air getting in, and there are 2 exhaust fans on the "roof" of the case (which has holes as well) for getting the hot air out. The temperature stays at ~27.5 - 28 C while the lights are on, and drops to 21-22 when they are off. The humidity stays at ~45%, goes up to 65% for a few hours after I water.
The main problems that I still see:
- new growth continues to have yellow tips, and has done that since week 2
- the older leaves keep dying (yellowing, then browning), and it seems to keep moving up (I remove the leaves once they are fully yellow)
Pictures of the symptoms: https://imgur.com/a/C9WFHQm (scroll down for more pics)
Thanks very much for reading this far, and for any help you might offer!
If I forgot any details, let me know!
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