Why is my plant yellowing - Please help

[Carly95]

My plants 3weeks old and still getting over being watered to much they picked up lovely and now tops are going yellow I don't think it's heat because they only under 400watt bulb and temp is between 25-28 so I don't now what's up they in canna pro plus mediam 5liter pots drainage is fine

 

[Carly95]

1.2x1.2x2m tent

 

[arteekay]

Checking your PH when you water?

 

[Carly95]

Ph is between 6.5 7

 

[Acyll1996]

Looks like nitrogen deficiency for me. Have you given nutrients?

 

[Major PITA]

I'd check the roots. You can sometimes learn a lot by getting a peak at what's going on below the surface.
Those pots are not full of grow medium. Looks like 1 gal, or less. Once plants are established, growing in small amounts of soil is more of a challenge, IMO.
I don't believe that "soil" has nutrients in it. Have you fed them anything?

 

[Carly95]

I did at the beginning but then thought I might burn them coz the medium reports to have several week worth of nuts in it but it says on the packet water with nuts solution after the initial drought but not sure what that means .

 

[four201976]

If you use something like Alaska Fish fertilizer 5-1-1 it won't burn your plants...if it's nitrogen def. then that will fix it for sure...if not no damage done. The initial drought means the time in which they say the feed included should last(I think). Good luck. Keep us posted.

 

[Carly95]

I got sensi seed a and b and sensi bloom a and b thay been in the medium now for 3 weeks any nuts in the soil would have been used up by now I think ?

 

[Major PITA]

I got sensi seed a and b and sensi bloom a and b thay been in the medium now for 3 weeks any nuts in the soil would have been used up by now I think ?

From what I've read about your soil, "Yes, they are ready for some food."
Go light. You can always add more, but it is not so easy to remove it.
Also, maintain proper watering techniques. If they don't need water yet, wait on the feeding until they do.

 

[Guano]

Ph is between 6.5 7

I don't know your medium but this seems high for proper iron uptake. Especially if you are leaning more towards 7 than 6.5. I've seen improvements in my grow when I started watering at 5.9~6.0. I use soilless medium.

On your next grow, I'd also try a few Smart Pots along with your plastic pots. I like the air pruning qualities of fabric pots and have found plastic directs the main roots to curl along the bottom. Much like you see in a Solo cup when transplanting. I also feel the fabric allows more oxygen to the roots since the entire pot breathes, not just at the top and the drain holes.