Flower is a farm product and it goes off the way farm products go off. Slowly, then all at once, and mostly because of things you can control. Four of them matter. Here they are, in the order people get them wrong.
Humidity is the one
Too dry and the flower crumbles to dust and the smell walks out the door. Too damp and you are growing mold in a jar. The range the trade works to is 55 to 62 percent relative humidity, and the easiest way to hold it is a two way humidity pack, the small square sachet sold for exactly this. One pack per jar. Replace it when it goes stiff.
Do not add anything else to the jar. Citrus peel, bread and damp cotton wool all show up in old advice, and every one of them is a way of introducing water plus whatever was living on the thing you introduced. Nah.
Glass
An airtight glass jar with a gasket is the whole answer. Plastic bags hold static, which strips trichomes off the flower and leaves them on the bag. Soft plastics pass air over months. If your flower came home in a glass jar, the jar is the storage. You are done.
Keep the jar reasonably full. A big jar holding a small amount is mostly air, and air is what does the oxidizing.
Dark and cool. Not cold.
Light and heat age flower fastest. A cupboard or a drawer at ordinary room temperature is fine. A windowsill is not. Neither is the shelf above a radiator or the top of a refrigerator, which is warmer than the room around it.
Not the fridge and not the freezer. Both cycle through condensation every time the jar comes out, and cold flower is brittle flower. The trichomes snap off at a touch. Freezing is a real technique, but it is a technique for material headed straight to a press, which is a different page.
Hands off
Open the jar, take what you want, close the jar. Every handful rolled around in a palm leaves something behind, and every minute the lid is off is air exchanged.
How long is it good for?
Honestly? Months rather than weeks, kept like this, and the first thing you notice going is the smell. That is the true answer. We can tell you how to slow it down. We will not print a date for a jar stored somewhere we have never seen.
We keep humidity packs behind the counter at 2 Eagle Street and we are happy to throw one in. Ask, or call (828) 222-4367. Every jar on the shelf has its lab report on Lab results, and how to read a certificate of analysis explains what is in one.