Greenthumb -
Certainly when we hear about leaf rolling on New Guinea Impatiens high soluble salts is the first thing we think of. If high salts levels are the culprit in addition to the leaf rolling you may also be seeing leaves that are very dark green and shiny with some rippling or waviness. The cupping is usually expressed on mature plants. If the situation is severe the cupping can be followed by some tip burn. The plants will also have poor vigor and may appear wilted even when the soil is moist.
Your EC levels certainly don't seem too high but acceptable levels vary depending on which method you used to test. We recommend using the Saturated Media Extract Method for the most accurate results. It is also important to routinely calibrate your meter for continued accurate results.
Did you leach the plants prior to testing? If so, salt levels may have dropped prior to testing. Remember that what you are seeing in the foliage is a delayed response to what is happening in the soil so salt levels may have been higher before testing.
If the plants have good vigor than your fertility rates are at a good level, however high EC can also be attributed to water quality, leaching frequency and the type of growing medium the plants are grown in.
It would be a good idea to have some media and tissue sampling done. That way we can also see what is going on in the tissue.
We can't rule out chemical applications. What have you made for chemical applications? A phytotoxicity to certain chemicals can be expressed as leaf rolling. It may not be from a recent application either so you have to think about all the applications you've made for the duration of the crop.
Do you have pictures you could post? You can also email them to rsiemonsma@eckeranch.com if that is easier for you. Pictures might help us get a clearer picture of you situation.
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