Day 42 from seed & I'm having real trouble with magnesium deficiency. It was very bad in my first two grows. This is my 3rd. I've had to remove quite a few dead leaves. I'm using Biobizz nutes, Light Mix soil. Ph of nutes is 6.5 & I've been feeding them Biobizz calmag at 1ml a litre of water. On Saturday I upped that to 4ml a litre. I'm in a hard water area, so I'm wondering am I overdosing on calcium? It's so bad, I have lumps of calcium in my kettle. Would I be better just using a Magnesium supplement or Epsom Salts? If so, what dosage of Epsom Salts should I use? I've searched for hours online & all I can find is the dosage 1 tblsp per 5 litres of water. But that's for a foliar spray I can't get an answer anywhere. ANY help will be very much appreciated
From pictures provided I don't see anything concerning. Definitely no magnesium deficiency. Dont expect to keep every fan leaf during flower moreso without a good defoliation. Without a good defoliation your plant will need more nutrients to support those extra fan leaves. During flower the plant is concentrating on creating flowers to receive pollen some fans will bite the bullet to conserve energy and also give energy for this process.
i agree with grobuddy pluck some fan leaves all the lower ones to start get some airflow going and try just buying spring water by the gallon cost maybe 50 bucks for a whole grow
Yeah I don't see anything to crazy those could be just old leaves or something...in my last grows I didn't have the nitrogen levels correct and it transferred over into flower.... mag Def sometimes has brown spots... nice plants tho Sent from my SM-G781U using Grasscity Forum mobile app
Really appreciate all your replies. I didn't do any training or defoliation. I thought it might be too late now to do any? Here's a leaf I took from half way up one of my girls yesterday. Lights come on in 2 hours, but other leaves were turning yellow & getting brown spots when I looked before lights went off today. I've only a few grows under my belt, but this says to me magnesium deficiency?
That is magnesium deficiency, if you recently finished the stretch portion of flower I'd think the plant pulled extra nitrogen, the splotches favor phosphorus deficiency however if you're just seeing the issue on a leaf or 3 with as many as you have I wouldn't worry too much. If the plant was riddled with deficiency that would draw concern If you ever do have magnesium deficiency it depends on nutrients you're using which method would be best to treat deficiency. If using liquid fertilizer go with a calmag solution, if using amendments use Epsom salt 1tbls per gallon of medium. Also good during veg even early on to give Epsom salt foliar sprays, once a week to every other week 1 tbsp per gallon of water.
I'd guess that it's simply a nitrogen shortage. Nitrogen facilitates a ton of metabolic processes in plants. It's a main ingredient for all things important in plants. Organic fertilizers generally need a much higher calculated ppm of nitrogen than mineral salts. I think it's suggested to dose 300-400 ppm of organic nitrogen. I'd used biobizz forever ago and didn't have good luck. I've seen a lot of sick plants with biobizz. I think you're simply seeing a nitrogen deficiency. Although magnesium may come to mind, it's relatively unlikely. You're already feeding cal-mag, and soils should already contain magnesium along with the base feed. It'd be one thing if you were on RO water in a soilless substrate. Being in soil and already supplementing cal-mag really makes it seem unlikely that you're experiencing a true deficit. I'm a big ole fan of simplicity. I rock single part formulas and keep it stupid simple. At this point, I would suggest upping the nitrogen levels throughout the rest of flower. I had very similar problems and that's what helped me get through it. The importance of nitrogen is vastly understated for cannabis in flowering. I think we've all grown too used to bloom nutrients being low in nitrogen and high in P and K. We need nitrogen throughout flower and a deficit can cause all sorts of manifestations that look like other problems.