yellow leaves

[Altfuel]

Hey Guys,
Need help with a problem. My plants are 4 wks into flowering. They are in soil (FF) and I am using Dutch Master flowering nutes as per directions. My problem is that the leaves are turning yellow from the bottom of the plant and moving up. It does not look like nute burn. The leaf starts to fade along the vien lines and slowly yellows out and then drys up. The whole process takes about a week. It started with the fan leaves and now is starting with the secondary growth. RH is about a steady 30% and temp ranges from 68 to 84 degrees. Great ventilation and have a fan on them. All plants are doing it to different degrees. What deficiency am I dealing with?

Any input is greatly apperciated.

 

[Altfuel]

also, the top 2/3's of the plants look fine and very healthy. Nice color green and the flowering is going fine.

 

[Hightide805]

yellow leaves is usually nitrogen deficiency... and in flower you don't use very much nitrogen, this is normal... if its not happening way too fast

 

[Altfuel]

Thanks tide...what is a good quick dose of Nitrogen?

 

[Stretchtastic]

you could add 1/4 str veg nutes. i assume that would help. someone else might know a better way.

 

[Hightide805]

you really don't need any nitrogen now... you want all your energy put towards making fat buds, phosphorus and potassium is more important now

 

[Racefan]

What is your ph? Could be the start of lock out. If your feeding an adequate supply of nitrogen to your plant it should not yellow out at any time. The only time I get yellowing is when I start to flush and the nitrogen supply is cut off.

 

[Altfuel]

I have not tested run off, but I water with a ph of 6.5.

 

[TorturedSoul]

Water to the point of run-off and test the first bit that comes out.

 

[Altfuel]

Thanks to all for the input. If I find that the run off is to a PH extreme, either to base or acid, should I adjust the next watering the opposite direction to help equalize?

 

[Altfuel]

I just tested the run off and it was in the "8.5 or higher" range. What's the next step?

Again, thanks to everyone for the input.

 

[Vexer]

Well I would first suggest you flush your pots and see if that helps at all, it could just be a salt build up. Ground lime and sulfur can also be used to lower your soils ph.

 

[Altfuel]

Thanks Vexer...buds are coming along nicely anyway...just don't want major trouble before I harvest in three weeks.

Thanks again to all that have put in their two cents. Need all the help I can get.