Foliage color can be affected by a number of things, one of them being genetic characteristics of the plant (think of skin/eye color in humans). Pro-TeKt can also have some affect on how green a plant is because it helps promote the production of chlorophyll, which is a green pigment common to almost all plants. I think it should be established that the greenest plant isn't necessarily the healthiest plant. IOW, there are ways we can manipulate plants to make them greener that aren't necessarily in their best interest.

For example, we CAN apply an Fe (iron) chelate, which supplies Fe bonded to an organic molecule, making it more readily available for uptake. While applying Fe in excess of what the plant needs to grow to its genetic potential within the limits of other cultural influences can make plants greener, it will also have a limiting effect on growth/vitality. Fe in excess can limit the uptake of other nutrients, particularly Mn (manganese) and P (search "antagonistic deficiency" for more). As well, its contribution to the TDS (total dissolved solids) level of the media solution and the increase in EC (electrical conductivity) of the same, DECREASES the plant's ability to absorb water and other nutrients.

One of the things that changes the color of foliage & blooms is the level of acid or alkali (pH) in cells surrounding the pigment. This is a consideration quite separate from the pH of media/media solution. As cellular pH increases/decreases, pigments change structure by bonding with different elements, which makes them reflect different wavelengths of light, which is what gives objects their color. We are actually seeing the color they are NOT, because what we see is the color they REFLECT. Added Fe causes the plant to reflect the green fraction of the spectrum as it approaches blue - or the darker green.

That said, it's unusual for there to be bonafied Fe deficiencies in plants grown in container media when using synthetic fertilizers because they usually all contain Fe sufficient to ensure the POTENTIAL for normal growth. The nutrition-related factors that most often influence foliage color are, a low fertility level overall, over-watering, and a high soil solution pH, with the high soil solution pH being the most frequent offender. Let's add high soil temps to the list, too.

Fe and most micro-nutrient's availability decreases as pH rises and the elemental nutrients begin to form insoluble compounds, which then precipitate (fall out of solution) and become unavailable. The fix is actually quite easy - acidify your irrigation or fertigation water.

The pH of my tap water is quite high - usually around 8.5-8.8. In the summer, when everything is outdoors, I don't see any pH related nutritional issues because I flush the soil thoroughly every time I water, which goes a long way toward preventing (bi)carbonate build-up and its accompanying increase in pH, and I fertilize regularly. In winter, when most plants are under lights and I can't flush as thoroughly (though I still DO flush) I often DO see some evidence of pH related deficiencies. As soon as I see foliage looking a little chlorotic, I acidify the irrigation/fertigation solution.

If you suspect a pH induced nutritional problem, and more specifically if you're targeting chlorosis or just want greener leaves, you can use either white vinegar or citric acid (at wine making supply stores) to acidify your water for irrigation. To fresh tap water, add enough white vinegar or citric acid to a given volume to bring its pH down to about 5.0. Note how much it took to reach your target pH, and add that amount of your acidifier whenever you water/fertigate. You'll probably see that chlorotic look go away, replaced by a more vibrant green.

Al

Al,

Thank you for your response. I have just Bren too busy to reply. I am betting that the h of my water is old, if anything. Thank you for the informative answer!!

I am going to find some Pro TeKt and start using it to see if it makes any difference. The difference in color is not huge, but Ai do see a difference, of course my a singapore Whites are much darker green (one of the many reasons I like them, besides being evergreen!). Mahalo!

What are you using for fertilizer? When you water are you flushing the soil thoroughly each time? Do you have any idea what the pH of your (municipal?) water is?

Al

Jennifer,

I just bought some ProTekt from theHydrosource.com. I want to try it out this year as well. They have a brick and mortar store in Covina, CA. Thought you would like to know.

Mae

Al, what excellent information. I really would like my greenhouse plants to be more healthy. I'm so busy with my gardens during the summer months that I quickly spray water with a garden hose and am not providing the fertilizer I should. I ran out and measured the PH in my potted plants and it is high. Most are 8 to 9. In addition, we have very alkaline water here. I am going to begin using some white vinegar in my water and I just purchased ProTekt in hopes that will help my plants get stronger and make it through our cold winters better.

I also read in another post that you stated it is ok to provide fertilizer all winter long. I hope I understood that correctly. If so, that is fantastic because perhaps I can get my plants in a little better shape by spring. I try to keep my greenhouse temps at 45 deg. During the day it is usually in the 60 to 80's and at nights that is generally when the temps drop into the 40's.

Thank you for taking your time to explain in such detail our plants needs.

To eliminate the potential of ammonium toxicity (a rather common malady that almost always goes undiagnosed or misdiagnosed) you should withhold fertilizers whenever the mean soil temperature is below 55*, and in particular, withhold organic nutrient sources, which includes fertilizers that get more than 40-50% of their N from urea. Plants just don't grow at those low soil temperatures.

I do fertilize in the winter with a weak dose every time I water, but I grow indoors under lights, so my plants are active all winter long. It's also imperative that if you adopt this practice, that you use a soil that allows you to flush the soil when you water, to prevent the accumulation of soluble salts in the soil that can impact the plants ability to take up water and spoil the appearance of foliage (dead leaf tips & margins).

I think the point of my other comment was to illustrate that though there is a plethora of anecdotal evidence that you shouldn't supply nitrogen to plants beyond a certain point in the early fall or late summer, there is nothing scientific to support this. Plants in nature have the same amount of N available to them in the fall as they do in the spring and summer, and while N is a necessary part of branch/stem elongation, it doesn't play a part in stimulating the opening of buds newly formed in late summer through early fall. Look to the increasing dark period (more technically correct than decreasing day length) for that honor. Additionally, plants will store N just as they store other elements, and the N applied in fall can be a valuable asset in spring when plants are waking up and N is more difficult to assimilate due to cooler soil temperatures. The higher nutrient load also means greater resistance to chill.

It's not unusual for municipal water supplies to deliver water with a pH >8.5. In fact, it's the norm because if it was less, the water would corrode plumbing very quickly. ProTeKt tends to raise Ph because it's very basic (opposite of acidic), so in your case there is probably a considerable advantage to be gained by acidifying your irrigation/fertigation water. If you're going to do that, would suggest that you get an inexpensive test kit that is used for pools, ponds, aquariums. Start with a given amount of water and add enough white vinegar or citric acid (from stores that sell wine-making supplies) to bring water fresh from the tap down to a pH of about 5.0. The pH will tend to rise to about 5.5 as the dissolved CO2 in the water gasses off. Use that to water and fertigate. It will stop the upward creep in media pH associated with high pH and hard water, and make the micronutrients more soluble and available. Often, adding a little vinegar to your irrigation water is all you need to green things up - the nutrients may be there, just unavailable because of pH issues.

Al

I usually use 1 tlbs of epsom salt to 1 gallon of water to green up my plants. Barbra

On another thread by Kimmie, I think it was "A Fertilizer Question", I talked a little about the ramifications of using supplements aimed at supplying only one nutrient and why that practice more often than not ends up being limiting, rather than a benefit. As noted above, there are a lot of ways to make a plant greener that are not good for the plant.

Epsom salts (MgSO4) supply magnesium (Mg) and sulfur (S), and S is only very rarely deficient in container soils, which leaves us with the assumption that any benefit derived from Epsom salts would come by way of its Mg content. The question that needs to be asked before you use Epsom salts is, "What leads me to believe I have a Mg deficiency?" If you don't have an answer or a reason to apply something, especially when it's an element or compound targeted at increasing the amount of a singular nutrient, you're better to forgo the application; the reason being that if there isn't a Mg deficiency, more can't possibly help; rather, it will be a limiting factor. That is a point that can't be argued without first refuting Liebig's Law of the Minimum, which addresses limiting factors.

Not only can applying Epsom salts when Mg is not deficient needlessly raise the level of dissolved solids in the soil (solution), making it more difficult for the plant to take up water and the nutrients dissolved in water, it can also create what is called an antagonistic deficiency of Ca. Ca and Mg need to be present in a ratio somewhere in the 2-4.5:1, Ca:Mg range. When that ratio becomes skewed through the addition of only Mg, the other nutrient (Ca) is more difficult for the plant to take up. You can easily create an antagonistic deficiency of Ca by applying Epsom salts unnecessarily.

If you're using a commercial soil, it's unlikely you would have a Ca or Mg deficiency because the soil would have been pH adjusted with dolomite CaMg(CO3)2, which as you can see supplies both Ca and Mg, and in a favorable ratio. The same is true if using your own soil made with dolomitic lime. Also, it's very unlikely you would have a Mg deficiency when using Foliage-Pro fertilizer, because it's included in the fertilizer in soluble form.

Those are the overviews from the perspectives of physiology and soil science. Hopefully they make enough sense that you'll want to incorporate them into your thinking. If all you take away from my offerings is that there are no magic elixirs that can make up for inappropriate nutrition supplementation; and that adding supplements targeting an increase in the supply of singular nutrients are far more often limiting than beneficial, you will have taken something worthwhile.

Al

Al, Thank you for the information. I will have to find a way to measure the soil temperatures as my greenhouse fluctuates from 40 deg in the evening to 70 - 80 deg during the day. I would really like to continue to apply a weak fertilizer throughout the winter.

I am a wine maker so I have the Citric Acid and the test kits to determine the PH and bring it down to 5.0. I will be giving that a try.

I do understand what you are trying to say about adding too many supplements can cause additional problems in the long haul. I do believe since we have potted plants, there has to be a happy balance of supplements. However, what that happy balance is I just have not figure out yet.

Thank you for taking your time to provide your scientific knowledge in hopes of helping me get some nicer looking plants.

Oh my goodness, what a lengthy and complicated thread! Jennifer, are you growing your plants in full sun in heat? If so, you might get darker green leaves by giving them a bit more shade. Maybe that's been mentioned already, but I didn't have time to read thru each thread.

You don't know how long the Armstrong plant was there or whether it's been in part shade for a while do you?

Dave,

Sorry, I have been away for a bit. The plant in question, it turns out, when I moved it to another location, thst the plant it was next to was a different color! The rest are all the same color. Yes, I do have mine in full sun for most of the day. Although they don't get the hot evening sun. I have them on the east side of my house, so as the sun sets in the west, the hottest part of the sun is stopped by the house. Except for two of my trees that are now in the front yard, they have been getting the hottest sun all day (one is a Sngapore White so it has darker leaves by it's nature).

The posts replying to this original thread are certainly thought provoking! Al, you raise so many more question! In the next day or so, I will post them, with pictures to support my question. Thank everyone! Mahalo!