Jiffy peat pellets are Ideal for starting your seeds without any mess. All you have to do is just add water and the pellet will expand once the pellet has expanded you can plant your seed. The pellet has a thin net holding it together. Once your plants are ready to be transplanted all you have to do is transplant directly into the ground or container and you will minimize transplant shock and root damage. This pellet is a 36mm and will expand (1.50in x 1.50in.)