Brix is literally measuring how much “energy” the plants has. A 2% brix plant will have relatively small leaves because at least one nutrient is the limiting factor, not light. A 15% brix plant is when light is the limiting factor, so leaves are huge and stretch happens, trying to get more light.
Chasing brix without tissue or sap data will most likely just drive you crazy. I’m not sure how long you wait before making changes, but when changing mobile nutrients brix is slow to react. IME the best way to chase brix without tissue data is foliar sprays. Foliar spray different sections of your garden with different salts, whichever raises brix the most increase in the fertigation solution. This isn’t perfect and doesn’t account for antagonism in uptake, but is about the best you can do.
So this brings up a question with the understanding that different cultivars will yeild different results. If one were to get tissue samples done, are there optimal times to of the cycle have them analysed? Perhaps one from veg, stretch, mid and late flower? Or is there a time to sample that would give a ballpark idea for ones environment?
@emdub27. Is brix directly correlated to flavor? All the articles I have found have to do with raising brix in tomatos for better flavor but, geared more towards organic inputs. I did hit them with a Ca foliar spray yesterday and they seem a little happier.
I only run commercial operations that are 10k+ sf. 90% ofvthe time we are running one veg mix from clone until flip and one flower mix fir the rest of the life cycle. So nothing is ever quite perfect.
I pull tissue samples out of my own gardens every Monday, but everything I own is hps assisted dep and I’m always chasing the weather.
As long as you understand all of the antagonisms involved, interpreting tissue data is relatively straight forward. The main problem you’ll run in to is that their isn’t published data on what to target, but if you keep tomato and chile pepper data in mind, you can get there.
It’s slightly more complicated, but yes. High brix plants have more energy available for higher level functions, terpene, anthocyanin, flavanoid and cannabinoid production. IME you see 2% or so terpenes on flower from average 5% brix plants and about 4% terpenes on a 12-15% brix plant.
Dark, leathery leaves are ultimately what i am trying to correct and seems to be consistent between grows. To my eyes, the buds themselves dont appear to be dark hued but i don’t have a visual benchmark besides my own grows or dried buds consumed over the years.
Could a simple upward adjustment of Ca potentially help in that regard? I always assumed it was too much N.
I have tried decreasing the CalNit but that ultimately leads to deficiency. I never tried increasing it, fearing it would just exacerbate the issue.
I assume you’re running the Jack’s at 321. That’s very close to Veg Bloom ratios, but with relatively excessive Mg levels. We only use high Mg ratios like that with hot weather and strains that we need to be basically solid purple. Mg, Ca and K basically compete for the same uptake pathway, so the ratios between them are very important.
If I ran that recipe in the average indoor facility I work with, I would expect to see a K deficiency.
When you look at old posts, they may be taken out of context. There are 2 prevailing ways most folks are running nutrients, similar to Jack’s and Veg Bloom or similar to HGV and athena. In general the ratios for each are obviously very different and can get confused with each other.
My new toy arrived today (brix refractometer) and I took a sample leaf from my plant which is @ day 54 of flower. I juiced it with a garlic press and i get a cloudy division at around ‘12’ on the scale. I’m assuming this is a pretty decent reading?
Is there a peak time to check brix or is this something you check on semi regular intervals?
Brix tends to rise through flower. Ideally check flower at 6-9 hours after lights on, it should be rising throughout the day period. 12% is pretty damn good, nothing to complain about there. It’s going to be very hard to improve nutrition at this point, because you have 90% perfect nutrition and there will be no visual cues to go by. Was the sap green, purple or milky green? Typically at that brix level, later in flower, you’ll see sugar induced anthocyanin production that makes some very pretty purple hues.
The detailed response is the the more diffused the division line is, the more differentiation there is with the ions in the sap. But typically a hard division line is a sign of a Ca deficiency because of how important Ca is for transport of other ions.
My raw salts should be here soon. Since i dont flower during the summer months, I’m going to spend the time messing around with some clones slightly varying a single ion and observing differences in growth. If anything, it’ll give me more insight on ratios and a better understanding of fertilizer in general.
One questions about brix if you have time. You mentioned foliar feeding single ions to look for improvement in brix if the brix levels are insufficient/low. At what sort of EC/ppm concentrations would i aim for when foliar feeding? How long after a foliar feeding would one check the leaves for improvement? A couple of hours, i’d assume? Thanks again.
I typically foliar feed all salts at 3-5 grams a gallon. Results from a foliar can be seen in a couple of hours. It’s not an exact science, but workable.
Checked brix again a few hours after the first on my plants in flwoer and it did increase but only a very small amount.
I checked one of my mother plants (different strain) in veg and it showed around a 10 on the brix scale and the division between the hemispheres was still diffuse but not as diffuse as the plants i have in flower. Definitely not a sharp division though, so that’s good.
I increased the amount of calcium a touch with calcium acetate and will check with the refractomer again in a few days and see if the division is more diffuse.
Playing around with some calculations in hydrobuddy and was wondering if there was an optimal ammonium to nitrate ratio? Does 1:16 NH4:NO3 make sense? I understand you dont want to go overboard on the ammonium, is this correct?
No real reason to stress about the NH4/N03 ratio. I honestly don’t even look at it unless it is going to be very cold. Whatever NH4 comes along with the CaNO3 is what they get.
Cal acetate will work in a stock solution, but you need to add sodium benzoate or potassium sorbate to stop fungal blooms from happening in the stock tank. You also now have an organic in a fertigation system that will encourage biofilm. A better way to go about it would be to drop the KN03 and add CaNO3, then make up the K deficit with KSO4. Be aware that the closer you get to CaN03 being your sole source of N, the more everything shifts to needing ratios more like Athena or HGV. I can tell you that I’ve been screwing around on a pilot plot with ratios similar to Athena and I can not grow a high brix plant without wildly changing it. The athena ratios in particular, put out decent bud and had high enough sap ph to not grow pm, I just prefer 12+ brix, so ipm isn’t an issue.
Thank you. I only mentioned it because i dont have any NH4 whatsoever from my calnit (purecal) and figured it’d beneficial to have a tiny bit in there.
The plan is to use stock A/B concentrates to avoid the weighing errors. I see what you mean, once you start dropping the KNO3 and adding more KSO4, it changes the N:Ca ratios drastically. I think i found a compromise so that i’d be running closer to the ratios i’m familiar using Jack’s. It’s tempting to change too many things.
I can use the calcium acetate to bump up the calcium in transistion.
Another question. I notice that when I mix Jack’s 5-12-26, my pH drops in the mid 4’s when mixing with ro water. Obviously, they must be adding some kind of acid to bring the pH down. I’d typically add a little bit of high alkalinity tap water to get my pH where I want it.
When making your own mixes, are there any tricks to get your pH where you’d like? I know silica raises pH but what if you want to lower your pH a bit? Would balancing amounts of MKP and something like PeKacid do the trick?
