Cut the vegetables into small pieces, and collect them in a larger freezer bag in the freezer. Herb stalks are collected separately. If you have enough, that's about two to three large freezer bags, then it's time to dry everything in the oven.
Take a baking sheet, put baking paper on it, and turn on the oven to approx. 90 C (195 F) circulating air.
First, dry the vegetable pieces, as they take longer. It doesn't matter if the vegetables are a bit on top of each other. With the help of the handle of a wooden spoon, leave the oven door a tiny gap open. This is necessary so that the moisture can escape.
After an hour or two, when the vegetables have defrosted stir them up and turn the heat down to 70 to 80 C (160 to 175 F).
Now you can dry the herb stalks. At best, you have a second baking sheet or a large casserole dish. If necessary, the vegetables on the first tray already shriveled, and you have gained space for herbs.
From time to time every 1–2 hours, you turn and stir everything. The drying process takes a couple of hours, around six, but that's just a rough guide.
Once everything is dry, blend it. Use a blender or electric grinder with which you can blend or grind dry food.
If you have the feeling that the powder is not 100% dry, then dry everything again briefly in the oven and then blend it again if necessary. What we definitely don't want is residual moisture, which means mold as a result.
Now you fill the powder in a mason jar, in which there is still enough space for salt. Namely, about 1/4 to 1/5 of the dried amount. So about 75% to 80% vegetables & herbs, the rest salt.