There are certain seeds that benefit from scarification or stratification. There seeds are usually perennials, shrubs or trees. If you’re not familiar with the terms the definitions are below.
The germination of some seeds is greatly improved or is only achieved with indoor gardening by Scarification. This is a process where you rub the seeds lightly between two sheets of sandpaper. What this does is enables the moisture in the soil to penetrate the seed coat. Seeds with a heavy coat or cover benefit from this.
I use this process for lotus seeds, shrub and tree seeds. Other seeds that will benefit from this process are Burnet, Salad; Clovers; Crane’s-bills; Liquorice Wild; Medic Black; Melilots; rock Rose; Restharrows; Trefoils; Vetches and members of the pea family.
NOTE: Use care when removing part of the sed cover. You want to only remove a small amount. That would be enough to help the interior take in water easier. If you remove to much you will hurt the seed and it may rot.
Stratification is a process I use every year. Quite a few seeds have to be subjected to a period of cold during winter before germination takes place in the spring. So when starting certain seeds you need to create this period of cold by adding the seed to damp sand and putting it in a plastic bag in the fridge for 6-8 weeks. You can also sow them in a cold frame in the autumn.
Species that benefit from this technique are Bellflower clustered, Bluebell, Burnet-Saxifrage, Carrot Wild, Cowslip, Honeysuckle, Lords & Ladies, Mignonette, Ramsons, oxlip, Primrose, Violets, Weld and all Sedges. Basically any perennial seed and about half the flowering shrub seeds that I collect I use this method to help the seed to sprout more naturally. I have a very high germination rate with perennial seed so I feel this process helps.
Sprouting and trees, shrubs and perennials from seed make the winter months go quickly and it fun to see what will grow successfully from a seed.
The only problem I have had from starting seeds this way is that sometimes I start too many of a certain seeds and storage until it’s time to plant the small seedlings, either in the ground or a holding bed, can be challenging.