Mg/Zinc Def ?

Hi Guys,

This is my first hydro grow and ran into a bit of trouble, I've spent today looking at what could be wrong with the plants and put it down to Mg or Zinc def. I understand epsom salts should sort it out if it is a Mg def and will go down shops and get some in the morning.

Growing Easyryder.

The plants are 3 1/2 weeks and and has just started to flower.

400w HPS
Ph 5.5
Ppm - 600
Temp 20c - 30c
Humidity 50 - 60
18/6 Lights
Feed 3 times a day for 30mins
Canna Hydro flores at 1/4 strength atm.

You can't make out on the pictures to well but also 1 or 2 yellow spots.

Any help would be great. Thanks!

your plant looks good. The tip burn is a tiny bit of nute burn. Ease up just a touch. and you'll be fine.

Not Magnesium or Zinc. The 30c temperature spike is the most likely issue. Even at 600ppm (which is EXTREMELY high for 1/4 strength) it still looks like there is some burn on the tips, which totally indicates a heat problem.

A touch more Potassium will be the solution if it is nutritionally based.

Being that you're running Canna Flores you're pretty stuck in your ratio. Try running RO water for a while and maybe you can dial in the nutrients a little better. The high ppms at 1/4 strength means that you're using more than you're stating or that your water starts out around 250ppm. If that's the case then the high levels of calcium and magnesium could contribute to uptake issues with the potassium. I think the 600ppm solution at 1/4 strength sounds suspicious because 2400ppm would be the extreme upper end for most plants without CO2 supplementation and perfect conditions.

If I could suggest any product for your system that might help out it'd be DynaGro Protekt. You could also try running reverse osmosis filtered water and supplement with just 100ppm Cal-Mag to keep a grip on that problem... if it is a problem at all.

The Protekt at 0-0-3 and 3ml per gallon will add about 20ppm of Potassium to your mix, plus an additional 30ppm or so of silicon. The silicon can help with other stuff too.

In all seriousness I'd start dropping the temperature first. Get it down to 27c maximum and that will help regardless. Then you can start looking at bottled solutions.