To elaborate on the already good advice given. I'd first like to point out that it's best to water the seedlings from the bottom, not the top. So, do yourself a favor, invest in a inexpensive seedling kit. They work perfect. The kit is something you can use year after year. The kit is great for indoors and/or outdoors. Each kit should come in two pieces; one that holds the dirt and seeds with bottom holes, and the other just a solid bottom flat (meaning no drain holes, so you can water from the bottom). Also, I find that the kits that include the propagation dome lids are wonderful.
I first start to germinate the different seeds in my extra pantry room inside my house. It has the right amount of light needed during the day. Then I moved them out to my large garden shed after they germinated. This will begin the natural habitat process that they need to thrive before the planting stage.
The tray underneath will hold plenty of water to water themselves for (1) week or more. Definitely check on them, as needed. Follow directions on the individual packets or other necessary sources regarding planting. Whether it be in the ground or in a raised garden, or extra large planters.
I suggest that you choose from all the wonderful fruits/vegetables that you and your family love the most. It's a great project with meaningful benefits. Good luck, and have fun!!
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