I have some Sweet Bay Leaf Laurel seeds (Daphne-laurus nobilis)
What is the best way to start the seeds indoors. I have read many sites and have many different answers. As the number of seeds are very limited I want to do it correctly.
I would appreciate your help.
Laurus nobilis, or Bay Tree/Bay Laurel/Sweet Laurel is a dioecious plant, which means they have male flowers and female flowers on separate plants. To produce fertile seeds you need to have both male and female plants close enough to each other for pollination to occur, unless you are able to assist with the transfer of pollen.
You may have acquired some fertilized seeds from another source. If this is the case, your seeds will require some pre treatment before they can germinate. Do your seeds have their pericarp? (the fleshy, blue/ black covering that gives them an olive like appearance. If your fruit is green or red it is not ripe and is unlikely to germinate). Studies have shown that germination success rates are greater in seeds that have had the pericarp removed. Gently remove to reveal the single seed contained within the fruit. If your seeds don’t have a pericarp they will be dry and the chances of germination are reduced by about 20%. You can soak dry seeds in warm water for 24 hrs prior to treatment to increase your odds.
Treating bought/collected/stored seeds prior to sowing them, known as stratification, simulates the natural Mediterranean winter/spring conditions- the native range of Laurus nobilus, before the seeds are able to germinate. Bay seeds experience a dormancy phase, and will not typically sprout until this dormancy is broken by a period of cold/moist (winter) or warm/moist (spring) conditions. The time taken to stratify Bay seeds depends on temperature and moisture conditions, but is around 6-8 weeks for warm-moist stratification (20 degrees C day/4 degrees C night) or 10 weeks for cold-moist stratification (4 degrees C, day and night.)
To stratify your seeds, prepare a growing medium. You can buy premixed germination substrate or good quality indoor plant potting mix. If you only have a few seeds, buying a soilless premix is cheaper. The seeds require a freely draining mix, so they are able to access moisture but are not wet. Your seeds will rot if the mixture is too moist.
Place the seed raising mixture into a clear plastic bag. Enough to cover your seeds and to keep the seeds separated from each other. Tie up loosely to allow for air exchange, or leave the zipper open an inch. Write the date on the bag so that you can keep track of the weeks. Place the bag in your refrigerator, set at 4 degrees C for cold/moist stratification. Be careful not to crush the bag during this time. The cold/moist method is more successful in domestic seed germination as it is easier to control the environment. To warm/moist stratify your seeds requires consistent ambient temperatures, without drafts or excess natural light. Often, as the light and temperature levels fluctuate, the contents of the plastic bag condensate causing the seeds rot.
Check once a week to see if the soil mix is moist and if any of your seeds have sprouted. Remove any seeds that have died/become soggy or grown mould. Lightly mist the mix with water as required. After about 8 weeks you may notice seeds germinating. At the 10 week mark, carefully remove all sprouting seeds and plant in small pots in the same mixture you pretreated them in. Keep them inside until the weather has warmed up enough to harden them off outside. Take care not to over water during this stage as they are prone to dampening off (being infected with fungal growth that may kill them). If they haven’t sprouted at the 10 week mark, check your fridge temperature and put them back in for another few weeks.
Bay seeds are considered one of the more difficult seeds to germinate and growers prefer to propagate them through stem cutting methods. This is not to say it can’t be done, but don’t be surprised if many of your seeds die. In ideal research conditions, botanists report 46% success rates in seeds that have been removed from their pericarps and cold/moist stratified prior to planting.