Starting Crepe Myrtle Seeds
As with all seeds there are many ways to get Crepe Myrtle seeds to germinate and grow, but the method below is how we start them.
The keys to successful Crepe Myrtle germination is light, warmth, moisture, and patience
Crepe Myrtle trees can take over 30 days to germinate so it is important to start with a sterile growing medium. Since Crepe Myrtle trees can take so long to germinate, we use a sterile medium so fungus or mold won’t grow before the seeds have a chance to germinate. We use screened peat with some vermiculite or sand added as a potting soil. You can also use commercial seed starter soil as these are usually sterilized for starting plants. You can also use commercial potting soils, or homemade potting soils made with compost, but you will have to sterilize them first by baking them in an oven set at 200 degrees for one hour. If sterilizing your own soil like this make sure any potting mixture does not have any Styrofoam added.
Once your soil mixture is ready you want to pre moisten your soil so it is slightly damp, but not soaking wet. Trying to sow most seeds in a soaking wet environment will make them rot before they can germinate and grow. Additionally if we're using a peat/sand mixture we will pre moisten our soil with a diluted (1/4 strength) mixture of water-soluble fertilizer like Miracle Grow. Commercial soils usually have some nutrient level in them and in this case only use water.
In the picture above we have taken a Tupperware type container and added our soil. We have gently patted down our soil and placed six Crepe Myrtle seeds on top of the soil and gently pressed them into our growing medium.
Like many seeds Crepe Myrtle need light to germinate, so we very lightly cover them with sand or vermiculite (uncovered seed on the left, covered on the right). Sand or vermiculite allows light to reach the seed and helps keep moisture around the seed.
We then put a translucent (clear) lid on the container with the corner of the lid cracked open, or in this case we have covered our container with plastic wrap (and secured with a rubber band) and have poked a few holes for humidity control.
We then have a small shop light attached to our container for a light and heat source. As our soil dries out we water very slightly on the side of the container being careful not to water directly on our seeds.
In this example we are using a small landscape type pot that holes in the bottom. We follow the sowing instructions above but place this pot in a shallow dish of water. We then cover with plastic wrap and place under lights.
Like all seeds Crepe Myrtle needs warmth and moisture to germinate. When using a incandescent light bulb, you should be able to maintain a 70-degree temperature on your surface soil and we recommend using a kitchen type thermometer to help you place your light at the proper distance.
You can also use a LED style grow light or fluorescent shop light, but this will not generate enough warmth and your might have to use a germination heat mat that is easily found on many online vendors like Amazon, Walmart, Ebay, etc. for around $10. It will take a bit of trial and error to get the right set up to maintain a temperature around 70 degrees. If you are missing one of the key elements (consistent warmth, light, moisture and patience) your seeds will not germinate.
Between two weeks and a month, with consistent warmth, you will start to see germination. The seedlings send up a thick stalk with two fan shaped leaves.
Once your seedlings are about 2” tall you can transplant them to individual pots. Slow and steady is the best way to introduce any seed grown trees and shrubs to your garden. We gradually increase the size of the pot, and in spring start putting our seedlings where they get 2 hours of direct sunlight per day for 7 days. After a week, and if threat of freezing weather has passed, we leave them outdoors in a protected spot when there only get morning sun. We generally only transplant potted shrubs and trees into our garden in the fall.