Sometimes we all need a helping hand!
If your favorite seeds are in the “hard-to-start” category, we have tips for you on techniques to give them a hand and get growing. The three basic methods for “encouraging” the hard-to-start seeds to germinate are:
Scarification – scar or scratch or nick the hard seed coat
Stratification – exposure to a period of cold temperatures
Soaking – hydrates seeds with tougher seed coats
Tricia demonstrates all the methods in our video, Seed Germination—Scarification, Stratification, and Soaking.
A seed is made up of a seed coat that encloses the plant embryo and the endosperm. The endosperm is the food supply for the early growth of the embryo.
Seeds that are hard to germinate often have a tough seed coat. If you are not sure if the seed needs scarification, soak a seed in water overnight. If it swells up, no need to scarify.
Popular seeds with hard coats
- Morning glories
- Sweet peas
To “scar” or abrade the seed coat and allow more water inside, use a pair of nail clippers or a file. Be careful. If you make a deep cut you can hurt the plant embryo just under the seed coat.
Some perennial seeds need moist cold to germinate. You can mimic the freezing and thawing of winter by putting your seeds in the refrigerator. First, mix 1 part seeds with 3 parts moist sowing medium, like perlite. Place the mixture in a sealed, plastic bag and put it in the refrigerator. Check once a week to be sure the mixture stays moist. The length of time in the refrigerator depends on the plant variety. When you plant the seeds, plant the moist medium along with them. This only needs to be done if you are not planting in the fall and allowing for natural stratification.
Some Common Seeds that Require Stratification
Soaking helps seeds with tough coats, and also draws out harmful chemicals. For legumes like peas and beans, soak them for 2-24 hours in room temperature water. Beets contain a germination inhibitor, therefore germination will be enhanced by a 2 hours soak in water.
Parsley is a special case and needs to soak for 24 hours, then have its water changed, then soak for a second 24 hours. Parsley is very slow to germinate and does best when seeds are in complete darkness. So cover seeds well and be patient when planting this out in the garden.
For more information, the very thorough, and highly regarded book, The New Seed-Starters Handbook, will be your best friend.
A short and clear booklet, with a handy list of hard-to-grow seeds and how to deal with them, is Starting Seeds Indoors, from the Storey Country Wisdom Series.