I am an avid gardener with over 4 decades of experience. I have never had a problem growing anything until I moved to a location close to mountains. I immediately noticed that my plants developed a light green color (chlorosis). Symptoms were yellow tips on top growth first then all leaves, leaves getting lime green, then light lime green with darker veins. If left without treatment leaves lighten, yellow then die. Growth stops. The yellow tips were very similar if not the same as minor nute burn. It also looked a lot like overwatering. Common advice would be to increase the nutes as they look like thy are starving and in fact this is what I did at first. This turned out to be the opposite of what I needed to do. I already had enough fertilizer in the soil, if not to excess. Checking the local tap water showed a high amount of calcium which I was told was from the high amounts of limestone the water ran through. The hardness ranges from 175 - 300 or so depending on season. I was at a loss to explain the chloriosis because I knew a lot of people who grew with similar hardness with no issues at all. Research shows that if the PH is high then a lockout of iron can result easily. My tap water is about 7.6 – 8.4. This article https://extension.uga.edu/publications/detail.html?number=B1256 says that “When the pH is too high, the micronutrients are less mobile and the plant cannot absorb enough, which results in deficiencies” and the accompanying photos looked very familiar. Foliar fertilizing with chelated iron solved my problem within a few days. One thing I did read a lot was the advice to add lime to your soil grows which in my case is the opposite of what I need to do. In my outside garden I made raised beds and added lots of peat moss etc in an attempt to acidify the soil a bit. This only worked for one season and I assume that the tap water is causing the alkaline conditions to reappear. In indoor grows the obvious answer is to use a high peat soil, again to attempt to buffer the water. This also didn't work at all. The plants get chloriosis very quickly and if not sprayed with iron die. This is a less than desirable outcome! The answer for me is to water with RO in which nutrients are added. This of course is an added expense, especially for me as tap water has always been fine. Again from the quoted website: “The alkalinity level has far-reaching implications because high alkalinity has a strong effect on the substrate pH. Of two water sources, one with a pH of 9.0 and alkalinity of 50, and the other with a pH of 7.0 and alkalinity of 300, the former will raise substrate pH very little, while the latter will cause a much higher raise in the substrate pH. In general, water alkalinity is more important in determining effects on substrate pH than the actual pH of water.” I think the change of PH happens much more quickly in pots because of the smaller volumes. So RO water with nutes PH’ed tp 6-6.5 it is. Bottom line this all resulted in Nute Lockout. This was not where I was heading at the start of this journey. I encourage anyone with this kind of issue to check the PH _and_ Alkalinity of the water they use. Good luck and happy growing to everyone.
[Yeah thats what I always thought as well. Seems it turns out not to be. Bad assumption on my part and resulted in very sick plants. Water Alkalinity vs pH in your Growing Medium - What's the Difference? | PRO-MIX Greenhouse Growing
Hi there @Ol Joe welcome to GC if you test your runoff, it tells you what the ph is inside the media. High amounts of CaCO3 isn't bad, just need a touch of acid and some epsom to counterbalance the Ca:Mg ratio. In peat moss, later on in flower the media gets acidic, but the CaCO3 in hard water helps it a lot. I've fed my peat grown plants with >7.0 hard water to counteract the acidity, so it helps. I would start with runoff feeds though, at least 30% runoff, so that you flush the old lime with fresh solution.
Thanks all good now. I was chasing it around thinking the girls were hungry or over watered. Since I had never even thought that lockout could occur with high Ca water it took a while to get there. Years of decent water with decent PH and Ca levels ruined me. The advice to ad lime didnt help either.
You guys make this more complicated than it needs to be, ive been growing plants as long as you, and never have issues. I make my own soil, nutes, and grow beautiful plants. Just for shits and giggles I tested runoff on my current girl and it tested 8.5 and she is flowering like a beast. Plants were growing and thriving on this planet long before we showed up. Its not rocket science
Yep same here. Amended soil (what they call supersoil nowadays) so there was no need to test PH. Plant the seeds and step back. I used to laugh at all the fuss. THEN I moved to a different area and it ht the fan. I just _knew_ that you didnt need to check PH in soil grows and I just _knew_ that water coldnt change the soil PH. Both these assumptions turned out to be wrong. All good now but I do wish I had the water I used to, it grew anything I wanted with zero issues.