Its probably not the hardness as much as it is salinity?

Yep. That's why I got a cheap RO system for seed starting. Minerals, including salts will build up over time and can kill your plants. It's not too much different than farming in an arid environment. There isn't enough rain to dissolve the salts out of the soil and the land eventually becomes unusable after years of being watered with ground water and the water evaporating leaving the salt in the soil.

hard water shouldn't be a problem But do you have a water softener? If so, that's the problem. See your other post for further info.

FWIW - the upper limits for TDS in water used for greenhouse production is around 640 ppm and nursery production is around 1280 ppm, so you're not in too bad of shape. It's also in your favor that the ratio of Ca:Mg is favorable, even though both are at the upper limit of what is considered acceptable .... 0-120 ppm Ca and 0-24 ppm Mg. Your pH is considerably lower than mine, and I have very healthy plants, so that's not too much of a concern. If you don't like the pH, add enough vinegar to neutralize the alkalinity & bring it down to 6.0, and you'll be fine - it'll stop the upward creep in your media pH, too.

While it's unlikely your water will harm plants outright, it can easily do so over time if you're not watering correctly. Soluble salts from fertilizer and irrigation water quickly accumulate in heavy soils when you only water in sips. These soils also contribute to individual or collective nutritional issues due to impaired root function and metabolism, so take a close look at your container soil.

Do yourself a favor and get rid of the hi-P fertilizer (for containers). It has no place in container culture unless you're using it in a very specific way to reduce the N supplied and are at the same time supplementing K, which I'm pretty sure you're not. There is probably never a need or reason for the hobby grower to use a fertilizer with the P % listed as being greater than 1/3 that of N, unless you are using it at very low levels to intentionally cause a N deficiency for some reason. It is very likely that your hi-P fertilizer is causing an antagonistic deficiency of Fe and/or Mn, as well as other micro-nutrients while it unnecessarily raised the levels of TDS/EC AND raises pH.

The most common cause of purple leaves, very common at this time of year, is a deficiency of phosphorus (P) because of cold soils. P is required to make ATP and ATP is needed to turn sugars to starch and to load sugar into phloem for transport. No P > no ATP > no move sugars/starches > anthocyanin (purple pigment) builds up > plant turns purple. The most frequent cause of a P deficiency is cold soils, which is why so many plants planted out too early turn purple. Don't use your hi-P on your containers - can't say what is going on in your garden.
A P deficiency is not the only suspect cause of purple leaves. Nearly any environmental condition that puts the brakes on growth and the accompanying use of sugars, but does not limit sugar production (photosynthesis) can cause anthocyanin buildup and purple leaves.

If only the outer edges of the leaves are purple, it may be a K or Mg deficiency. If the center of the leaves are also purple, it could be too much Ca in the soil or the result of too much water in the soil blocking uptake of P and Mg.

Read more about fertilizing containerized plants here.

Al

Thanks for all the great posts! No Im not using softened water. Very interesting read on container ferts. I was using a 0-10-10 for my 'bloom', I also tried a 2-15-0 bat guano a while with terrible results. Ive been going more light and more frequent on everything then I used too. So potting mixes tend to hold on to P strongly, and in an available form? More then my clay loam garden soil?

The brassicas I have with purple leaves and slow growth I realized looked like a P deficiency. I hit em a few times with my bloom and didnt see improvement. I thought about the cold but this should be perfect weather for them! Rainy with days in the 60s nights 40s. My old house was too cold, they sat all winter with frosty nights and waited for spring to grow.

My sodium and chloride avg low 40s. Is that high?

It's not so much that they hold onto them strongly, more that popular bloom formulas like 10-52-10 supply up to 30 times more P than your plant needs or can possibly use (relative to N). This has a horrendous (and unnecessary) impact on TDS and EC. How can we expect to have any room for all the other nutrients and still stay within reasonable limits of TDS/EC when we're over-supplying P like that ....... not to mention P's affect on pH and micro-nutrient availability.

Na should be 0-50 and chloride 0-140 ppm.

Al

Ok I thought some of your posts talked about how it was much worse in containers to use a high P and in garden soil it would be a bit more apropriate. So would flushing get rid of my excess P? It was mainly derived from phosphoric acid in my 0-10-10 liquid bloom.

It makes sense that this is whats happening to my plants, as well as my waters TDS being high perhaps. I seem to have a severe lockout. Even if I gave more N with fish emulsion the leaves didnt green up, they just seemed like fert burn, curling under and tip burn. It seemed to start when I gave the high P guano, which Ive never used before. How does anyone ever grow plants with the super P bloom formulas?

Isnt it conventional wisdom with hard water that if you simply flush the soil periodically with heavy watering you will flush the accumulated salts and avoid problems?

Yes - it would assuredly help to get rid of any hi-P charge in the medium now.

I often listen to people swear they need bloom-booster type fertilizers to make their container plants bloom, or for some other reason, but I too went through what you're experiencing many years ago.

I don't think the wisdom is all that conventional, but it IS wisdom just the same ...... flushing your soil every time you irrigate is the best way to water your plants. If you can't do that w/o risking root rot because of prolonged saturated root conditions after a thorough watering, you need to evaluate whether or not you're using an appropriate medium.

Al