varig8

As I mentioned earlier, and in a few other threads concerning variegation, fertilizers will not change this mutation in plants. Since the majority of these variegates are unstable (they are not genetic mutations) they will each vary within each particular plant pertaining to the amount and distribution of the mutant tissue. There are basically 3 main layers of tissue which make up the leaf, each lying on top of the other. In the apical meristem while the leaf tissue is developing, these layers swirl around on top of each other in opposite directions. Each has its own sectors of patterning concerning where the white and green is positioned. As the leaf is produced and grows out they then end up in the position that they will remain. If you look at the back side of a variegated leaf, you will see that the variegation pattern which is exhibited on the top of the leaf is not always the same as what is on the underside. There is only green tissue and white tissue. But, you will notice on the leaves of the Ae ae, for example, that there are varying shades of greens and 'grays'. They are all gradations of green and white. For example, where you see gradation of greens, this is where one layer of dark green has overlapped either partially or fully on top of a layer of white tissue to form a sector of light green, or, all of the layers of mutant white landing on top of each other would produce a sector of clear white, normal dark green on top of normal dark green=dark green, and so on. If you hold up a leaf to the sun and peer through it, you can oftentimes see where these patterns have landed to form the sectors of different coloration. Its quite beautiful to see this. Fertilizers will not affect this process. Since these are not stable genetic variegates, any notice of them 'greening up' could only mean that the amount of variegation produced during that time period would have been produced as is, no matter if there had been any introduction of fertilizers or not.
Now, having said that, if you would happen to have a plant like a philodendron that shows only a very slight bit of variegation on a single stem, or on a few leaves, most likely it would be overtaken by the plants natural habit of producing mostly normal green tissue (leaves). Since the variegated portions are weaker and not in abundance, the normal green growth can over take it and it would most likely disappear in time. Fertilizing this philodendron would only hasten its growth, thus allowing the normal green tissue to overtake the variegated parts quicker-BUT, it is not the fertilizer that is responsible for the lessening or disappearance of the variegation, it is the growth of the stronger normal green plant. In a genetic variegate this point would be mute as each leaf would be identical to the other; in other words, they are pretty much clones of each other and do not exhibit leaves different to the others, so fertilizing would also cause no difference in the coloration or patterning of the tissue which does not contain chlorophyll.