some help needed please

started out good approx. 6 wks from seed, the 2 on the left are cluster bomb and mango , on the right grapefruit and double berry. been using jacks classic 20-20-20, 1/4 teaspoon per gallon every feeding ph at 6.8. The tips on the c.b. and mango started to turn yellow and then the leaves started to turn also, so i flushed them about a week ago with water, i thought it was overfeeding. Also the 2 other ones are starting to yellow a little, any help would be appreciated. I feed them all last night same dosage + added 1 teaspoon calmag per gallon , I'm using promix soil, 400 watt mh about 24 inches above, temp approx 84-87 light on 75 light off. Any suggestions, thanks

a 1/4 teaspoon is a lot less than Jack advises on the label

I use jacks and do 2 teaspoons per gallon per feed

looks to me like they want food

and when ya run out of all purpose get his Citrus FeeD 20-10-20 you'll be glad you did !!!

i've been using Jack's 20-20-20 for years. your plants look nitrogen hungry with possible calcium and or other deficiencies. i use a TBS of Jack's for a little over a gallon of water. after watering the soil i spray the leaves, or just pour the mixture over the plants. cal/mag would probably solve the calcium problem. GL

even though i feed them last night , should i flush them with the stronger nutes? or wait till they dry out, which could take 5 days

Agree, it looks like they are hungry and have a cal/mag issue. In addition, looks like you got some heat stress going on there, get those temps down.

I wouldn't necessarily flush, if you feel they have a ways to go before their next watering, I would consider foliar feeding them the nutes. They will only use what they need and may bring some of the areas back. The dark brown spots will not recover.

Good luck and keep us posted.