New Grower: Need nutrient advice

[Bringreen]

Hi everyone! New grower here.

My 8 seedlings (all mystery bagseed) survived transplanting from soil to coco. the fast growers are beginning to yellow/lime green at new growth sites. It’s very noticeable under LEDs. Wondering if I over/ under fed them. I’ll try to attach images.

Here’s my current setup:
Coco and Pearlite mixed in 4” nursery cups.
PH’ed RODI water with Flora Series nutrients and Calimagic
Cheap LED panels 75w + 15w about 12 inches from plants.
(PAR450 LED and digital timer on their way)
6” desk fan for circulation.
Temps between 77-82 degrees.
Humidity fluctuates between 45-74.

Here’s my question(s)
if my substrate is still not dry after 3 days, is it ok to water seedlings? Any suggestions for nutrient concentration/scheduling? Interested to hear setup advice as well if willing.

For some reason, watering has me completely puzzled. Yes, I’m probably overthinking it, but what began on a whim has grown into a mild obsession, and now I want these babies to thrive.

[Daskahn]

Here’s my watering advice.. mainly because I’m alfread if overwatering, if it rains outside water according to how much it rains.. if it doesn’t rain don’t water.. lightly mist the plants right before the light goes off for the night..
as for the color change.. my guess would be the plant is getting used to the change in soil composition

[Darroldo]

I germinated my seeds in damp paper towels and then planted in pre watered (day before) small pots with Coco coir and perlite 3-1 ratio,10ml Canna A + B in 10litres of water PH around 6.0. I watered again 4 days later with same nutrients. After 7 days I planted into final big pots with 2/1 mix of coco and perlite, since then I have upped my nutes 2.5ml/10l water each week and water plants every 2nd or 3rd day depending on weight of pots (dry pot light, wet pot heavy) day and I am now at 22.5ml nutes/10l water with no sign of nutrient burn. I am using the Canna grow guide with slight reduction in the amount of nutes recommended. One of my plants is not as good as the other two with everything the same so suspect a weak plant. It was the last seed to germinate

[sgiacomo]

Checkout feed chart for GH products on their website. https://generalhydroponics.com/feedcharts

[Bringreen]

Thanks for the link! Reminds me I need a TDS meter.

Went ahead and watered them earlier today with a diluted mix since the coco felt dry around the edges, and didn’t hold back either. It hasn’t rained here in several days and I cant trust the climate where I’m from.
It’s exciting to watch the smallest changes in these plants. They’ve begun developing their first fan leaves
still a little yellowing visible under LEDs. Can’t tell if they’re deficient.

Next watering will just be PH’ed RO/DI water (maybe some CalMag with it) for a good flush.

[Bringreen]

[gbauto]

Hello, Bringreen
Coco needs to be treated like a hydroponic system. It isn't soil and doesn't hold any nutrient so you have to supply them 24/7. DO NOT let the media dry out.
Did you buffer your coco before using it?

https://generalhydroponics.com/feedcharts

Use the flora series drain-to-waste. Ph the solution to 6.0 and water to runoff. You'll have to determine how often to feed them and it's a good idea to flush the pots of salts once in awhile.

[Bringreen]

Thanks for the info, gbauto. My attempt at buffering was amateur at best: soaked coco and pearlite (already mixed) in RO/DI water with Cal-Mag; 1 tsp per gallon for an hour or so.

At that time, my first PH test was happening as well, so there’s no telling how off I was... After reading more though, it looks like a higher concentration and longer soak might’ve helped. This may be wrong too. If any suggestions feel free to stop me where I am.