beckygardener said:One more question .... is there anything that can be added to the soil to help the daylilies better handle heat stress? Compost? Micro-nutrients? Lots of water during the hot months?
Adequate nutrition would help but without any testing you don't know what might need adding. I wouldn't add micronutrients without knowing which, if any, you need because they can be toxic if added in too large an amount and they are needed in such small amounts that the difference between adequate and toxic is also small. The soil pH also significantly affects the availability of nutrients and for micros the lower the soil pH the higher the availability in general (availability can get too high in fact, if the pH goes too low). The soil pH can safely be lower in soilless media than mineral soil though.
The major nutrients are also important in heat stress, you need sufficient N and K but not overdo the N. If you were to use something like a complete NPK fertilizer with micros it should cover you (again with the caveat that absent a soil test you don't know the ideal ratio).
In plant nutrition the "law of the minimum" applies. If even just one of the essential nutrients is deficient the plant will not do as well as it could.
With water, adequate water will help with heat but you also don't want to over-water. It's especially important to take humidity into account because if humidity is high the plants don't take up as much water as if it was dry, or windy. Also you don't want to frequently water just the soil surface because it causes the roots to be shallow also and roots near the soil surface would get the most heat. You need to water deeply and then not water again until the soil at root depth is getting dry. Watering deeply enough can take a lot more time than one might think, I learned that the hard way.
