Yellow flowers clusters

In my opinion, the yellowing at the top of your plant looks like a sulfur deficiency or maybe the early signs of an iron deficiency. These issues usually show up as yellowing in the new growth, while the older, lower leaves stay green.Ensure your pH is in the optimal range for nutrient uptake.

Make sure u give them enough nutrients and also that ph is good. I had similar problem. Check the run off if u can.

Some Nutrients aren't being absorbed or your not giving the micro nutes the plant needs like others have pointed out. Definitely nothing to do with the main nutes nitrogen, phosphorus, potassium, calcium or magnesium.

Have a chart! https://420life.com/wp-content/uploads/2021/10/Marijuana-Leaf-Deficiency-Chart-scaled.jpg I would guess this is Fe or S based off new growth. but if it corrects in a days time I would not think about it to much.

no cap

If your plant aint looking like that mate, you are a loser with slow growing plants and will have minimal yields, be happy about it. They just cant keep up with the nutrients they need for the grow and if you dont underfeed them its the best sign you can have

Will add this to the advice you've been given so far. I would make sure that fan in the picture isn't blowing right on the plant. I see your lamp is around 17" Most people give way to much light in veg and early flower IMO. 24" and no more then 40% power should be required until after the stretch, then start increasing each week until middle of flower. Then lower back down again toward harvest.

new growth is yellow with thin blades... could be excess p or k. You can look on any leaf symptom chart to verify these symptoms. if you recently switched to some so-callled flower formula, they often have way too much p and k. worth a look. troubles with trace elements is really rare in soil or soilless... more often related to pH or some other nutes concentration locking it out. Though in these contexts you often see more than 1 type of symptom, but not always. as usual, what you see is not discrete. There are more than 1 cause for most leaf symptoms you see. Few are as easily diagnosed as a nitrogen deficiency. the progression of the paling and working bottom-to-top makes it fairly unique. a whole bunch of stuff can cause interveinal chlorosis.

Would say rapid grow, but even older leaves exhibits symptoms, so only one thing - micronutrients. Totally agree with Organoman. Think he gave you right answer, i would give same at least ....

Since it is starting with the newest leaves, it is not nitrogen, potassium or phosphorous.......it is not cal/mag either. To me it looks like a minor nutrient issue........either zinc or iron...........maybe both. A dose or three of soluble trace mineral/trace element mix applied to the root zone should fix this issue. Souble trace mineral mixes should be available from any decent garden centre.

Hey there the plants are looking good. I think if you top dress with some worm castings and myroinhaze. Also hit it with some cal mag preferably cal mag that has some nitrogen should be enough to get rid of the yellow. Also keep in mind if your plant is still growing super rapidly sometimes it's just hard to stop that from happening when it's already started so be careful not to overdue it tring to fix the yellowing because here soon the plant will not need nearly as much nitrogen.

I looked at last week compared to the recent week and yeah everything looks good but the new growth. She looks hungry if you didnt just do a feed maybe get one in. If you did just feed give it a couple days to take effect. If its just the plants look then it should work itself out by then. Dont panic she looks great any change you make will take a little bit of time to show. Good luck

Calcium magnesium

I guess its either nitrogen deficiency or you need to use

I think it's just transitioning. It's not uncommon at all for new growth to appear pale, especially when it's growing fast(like when they start flowering stretch). Older growth looks healthy. I'd be willing to bet that the newer growth will green up more as it matures.

There can be only three reasons: 1 excess light, 2 lack of nitrogen and 3 characteristics of the variety. But I am inclined to believe that it is an excess of light; I think 50% of the maximum lamp will be enough for her.