The first step when stacking pots is to remove all of the soil from the bottom of the pots. Remove any pots that are cracked or damaged, and make sure the potting mix is well drained. You can use a garden trowel to scrape out the mix from the bottom of the pot. Fill the bottom half of the pots with the same soil mixture as the top half. Then fill the pots with a new potting mix. For most plants, fill the pots up to two-thirds of the way with potting mix. Fill the last third with either vermiculite, peat moss, or perlite.
When it comes to planting, you want to start filling the pots with your seeds, seedlings, and cuttings. Start with the seeds and seedlings first. If you have a tray of seeds, you can put them in the middle of the pots, filling the pots halfway. Then fill the rest of the pots with the same soil mixture as the top half of the pots.
For the next step, you will need to transplant your seedlings. Take each plant out of its pot, and remove the roots from the potting mix. Place the plant into the new potting mix in the bottom half of the pot. Do not push the plant into the soil, but place the root ball gently into the new potting mix. Add some more potting mix on top of the roots until they are covered. Plants should be watered every day for the first week.