I'm a bit confused by your question but maybe you can clarify.

1. You want to know about a hydrangea for the first 16 weeks ... from when exactly? Are you talking about planting from seed or perhaps 16 weeks from planting a store-bought 2 gallon plant?

2. There are several hydrangea species which are likely not going to have the exact same requirements. Are you asking about all of the species or one in particular?

3. How are you defining the amount of nutrients a hydrangea demands? Do you mean what it demands in order to stay alive or what it demands in order to thrive and bloom and look nice?

Beyond that, I think it would help to have a better understanding of what you are trying to accomplish. I'm confident that the people here could provide you information about what nutrients in terms of the amount of fertilizer and sunlight that were provided to their hydrangeas but depending on the academic purpose, this may not be what you need.

How about this 1- soil....moist good drainage maybe a little sand?..2 Sun Location...morning sun/afternoon shad...3 -WATER check often ... Maybe maybe a little fert....Ok you Pros don't beat me up just trying to help

Thank you all of you for your valuable help.

I will clarify the points identified by Allison:

1. The nutrients demand for the first 16 weeks since they were planted in a 2 gallon pot. The consideration is for a soil less media at pH of 6.

2. The nutrient demand is refered to all species in general, not one in particular.

3. The nutrient demand I refer to is the amount of different nutrients (Nitrogen, Phosphorus, Potassium, Iron, Manganese, Boron, Zinc, Calcium, Copper, Nickel, Sodium, Cobalt and Silicon) during these 16 weeks to get a complete develop and look nice.

I suppose this kind of technical information must be obtained from a technical sheet from a nursery grower os someone like this, and I have seen technical data sheets for other crops, but unfortunately never for flowers...

Thanks again to all of you!!!

Good luck , I'm just a kid (76) who likes to play in the dirt!!!

perfumeria, such things exist for all greenhouse production crops, which certainly includes hydrangeas, however one often needs to subscribe to industry-related periodicals to obtain that detailed information. And hydrangeas tend to be manipulated by greenhouse growers more so than many other plants with growth hormones and regulators to generate heavy flowering on quite young plants. So the nutrient info you may receive may be artificially skewed with that focus in mind.

The rest of us who just grow and enjoy hydrangeas don't get very detailed about fertilizing.........for containerized hydrangeas, I just supply an early spring dose of a CRF like Osmocote and call it good :-)) Inground planted hydrangeas get even less attention from me - only a good mulch of compost.

Thanks a lot, you points of view are great!