I only have a PH tester, one for soil and one for water. Not sure what EC/TDS is?
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Soil probes like this one aren’t very reliable to measure soil PH.
The electrodes have to be perfectly clean and polished and the soil has to be near 100% saturation. Even then they aren’t very accurate and the needle will drift. An EC meter is used to measure conductivity of a solution. You can use it to measure the strength of your nutes and runoff. It takes most of the guess work out when and how much to feed so your plants don’t have to overcome huge shifts in the root environment. To put it simply EC is the strength of the solution and PH is how efficiently each nutrient in the solution can be used.
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Ok, thanks. Should run off be the same as what you feed the plants?
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No it will vary. Then next time you adjust up or down to keep in range.
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it’s normal for runoff PH to drift a few tenths up or down from your input. Target EC is a little different depending on your medium. I think I saw you were in soil. In soil you want maintain a runoff EC between 1000uS and 2500uS. You will charge the soil with a feed when runoff is close to 1000uS then use plain ph adjusted water the next few events until it drops back down and it’s time to feed again. It can take a few tries to figure out how strong to mix your nutes to charge your soil back up to full, but start small and increase a little each time you feed and eventually you’ll get it.
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The meter I have reads us/cm- ppm and ph. Will that meter work for run off?
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That’s it. uS/cm (microsiemens per cubic centimeter) is the unit of measurement and EC (electrical conductivity) is what you are measuring or the system of measurement in the same way that meters is the unit of measurement for the metric system of length. Your just measuring how well 1 cubic centimeter of solution conducts an electric charge.
PPM(parts per million) is also commonly used in place of EC but to keep things simple and avoid the math(it’s pretty easy but a lot of people don’t want to learn new math to grow weed) necessary to convert back and fourth I stick with EC. Just know when you discuss these numbers you will need to be clear about which system you are using.
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So I got the spider farmer se 4500 and the chart they give is not clear. I have it at about 20 inches at 80 percent. Is that reasonable. The part I read says 12 inches during flower and 100 percent, seems a little much to me and I don’t want to burn the plants. Anyone have any advice on this?
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The important point is to dial it up slowly. Cannabis is one of the most light tolerant plants on the planet, but they need time to adjust. For flower you can start around 60% and 18ish inches and dial it up a few % wait a few days to see how they respond and repeat until you reach max. That will allow them to acclimate. By mid flower 100% @ 12" is perfectly reasonable. When you hit the ripening phase dial it back to around 80% till they’re done. The happier the plants are the more light they can handle, but water, feed, RH, and temps need to be adjusted accordingly. Light intensity is like the dimmer switch that turns the plants metabolism up and down.
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Will do and thanks for the advice. A few are already at 6 weeks, those are the ones that I posted here. I figured out the PH and got the new light, I’m just hoping they turn out ok. The other plants are only a couple weeks into flower and are doing great, some of the leaves are getting lighter green for some reason but those look real good. Thanks again for helping.
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It could be that they are adjusting to the new light. Give them a few days to see how they respond.
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They started doing that before I got the light, the others aren’t doing that. It’s some of the lower leaves, the uppers are dark green. They aren’t so light that they are getting yellow, just not as dark as the upper leaves.
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Sounds like they have gotten a little hungry. Low N is usually the cause of bottom up yellowing. If it continues to spread upward you might consider bumping up the N ratio till the 2nd or 3rd week of flower when they stop stretching and demand for N goes down.
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Thread has lights and soils discussions.
You have describe most of my previous runs.
Forum friends have helped for all obstacles encountered.
Awesome learning available from sharing.
Welcome.
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Ok, thanks. I will keep an eye on them for a week and see if it gets any worse. Once leaves turn lighter green, do they ever get dark again?
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Not really, usually any deficiency damage is permanent. You have to watch to see if it spreads to determine if it’s getting better. I take a lot of pics when I start seeing issues so I can compare to see if things have changed.
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This is the yellowing I was talking about. The plants do good until flower. I water about every 3 to 4 days. PH is tested every time usually about 6.1 to 6.7 Feeding general hydroponics trio and big bud. Soil is happy frog with perlite. I am at a loss why my plants do this every time.
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Those do not look bad at all. Really. I have had much worse finish with fire smoke. Late flower. Some plants will naturally shed leaves and fade at the end. No matter how perfect the grow is. I think you are gucci. Just stay on point with feeding and ph no extreme changes are needed in my opinion.
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Dont need a booster with that nutrient line. Overfeeding P/K has its downsides also.
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Ok thanks. I am only worried because the last plants did this and continued to get worse. It’s the first pics I put on here up top. These plants are only 4 weeks into flower and are slowly getting lighter green and spreading a little
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