Answer: Your seed packet should give instructions as well as have an estimated germination rate listred on it, this would assume the seeds are fresh and have been stored properly -- cool and dry. If the seeds are older and/or if they were not stored under ideal conditions, the expected germination rate will naturally decrease. Oregano (Oreganum vulgare) should germinate in about two weeks at room temperature, but the catnip (Nepeta cataria) can be a bit trickier. ONe reference suggests germination at room temperature for 3 to 4 weeks, then if that does not succeed, chill the seeds for 2 to 4 weeks and try again. (A home refrigerator will work for this. Wrap the pan in a plastic bag to maintain humidity while it chills.) These seeds also need darkness to germinate. (You can enclose the pan in a dark colored plastic bag to provide that.)
Most gardeners plant their seeds in a barely damp soilless potting mix and enclose the container in a plastic bag to maintain humidity. Set it in a bright location but out of direct light at the suggested temperature. Check often for germination and remove the cover and move to very bright direct light as soon as germination occurs. Keep the soil slightly damp, not sopping wet and never bone dry. Fertilize with a very weak soloution of water soluble fertilizer such as 10-10-10 about once a week. When the seedlings have their first set of true leaves, transplant to small individual containers such as cell packs. When they outgrow these, move to larger containers. Continue to fertilize lightly per the label instructions. Trim them back occasionally to harvest and encourage dense growth. If you have a cat, be prepared for it to damage your catnip.
Clay pots can be better for plants that require perfect drainage or if you tend to grossly overwater, but in many cases the plastic containers work better because they are not porous -- this helps keep the soil more evenly moist especially during hot weather when the soil dries out so fast. If you prefer the look of clay you can set a plastic pot inside the clay pot. But, it is a matter of personal preference.
I hope this helps, good luck with your herbs.
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