HELP! Stunted Seedlings Starting to Yellow - 3 Weeks Old Outdoor Soil Grow

I'm struggling with these plants. I've planted 4 different seeds (all different strains) and they are growing at a snails pace.

They are 3 weeks old and hardly growing. They are getting pale and I don't know what to do.

They are planted in seed raising mix. 3 days ago I flushed them with plenty of water. Added a bit of dolomite lime. Then I gave a weak feeding of seaweed fertilizer (14.0 / 1.4 / 9.0).

I've measured the tap water at around 6.8. The run off was slightly under, about 6.5. I haven't been overwatering or underwater either.

They are have been out in full sun. About 11.5 hours a day at the moment. Temp 18-28C (64-82F).

I put them under a 100w cfl last night but I reckon they looked even more yellow by morning.

The 4th seed was planted about a month ago. It had hardly been growing either. Different soil. I took it out the pot and removed a fair bit of soil and put it in the ground. It's not growing like crazy but at least it has greened up a bit.

Here's some pics...

In another thread this was caused by too week nutrients. When the grower increased nutes significantly (almost a do-or-die increase) the began growing. Odd to me because when I've withheld nutrients to slow growth it immediately manifested deficiencies (yellowing, blotches).

What is the ppm of you water before adding nutrients? I've had stunted growth due to inappropriately high ppm tap water. It's like junk the plant can't use and competes with what the plant can use. It should be around 150ppm. If it's higher, you can mix it with bottled water to get it down to 150ppm.

Unfortunately I don't have a meter to test PPM.

I'm thinking there could be a possibility of a water problem. Bit weird. There's a rain water tank here, the veggie garden really struggled when I watered using it. Only certain things like spinach, beans, radish would grow. Other veggies got stunted and died.

I switched to using tap water on the veggies but I'm not sure it's any different. Tomatoes, eggplant and herbs don't do too well. Spinach, zucchini, pumpkin, chilies, radish, beans grow fine. I can't find information on what plants prefer what so I don't know how to narrow down the problem.

If you planted in seed starting mix theres almost no nutrients in that stuff. Its just for tiny little dome trays or peat pots. Get it in some real dirt mister, go feed them some fertilizer too. But dont go crushing them with it to compensate lol good luck.

I thought the seed raising mix would get me past the first leaf set though. The other plant not pictured was straight into some prefertilized potting mix and it still ground to a halt.

Ok so the last plant you planted in regular soil is doing better than the first ones in seed starter? Theres no numbers on pictures or anything lol, its tough to tell whos who?

Sorry mate, in my mind it was all clear, but that doesn't help anyone else

I described the 4th plant above. It was in regular potting mix, it struggled the same as these ones. I took it out after 2-3 weeks, broke off much of the soil and planted in the veggie garden. It hasn't taken off but the yellowness has gone and it's slowly growing.

Maybe nute sensitive strain!?

4 different strains, autos and regulars.

wouldnot said:

4 different strains, autos and regulars.

Click to expand...

Weird I would be checking water source ph of medium watch for not over watering if that helps