Discover what you need to know for growing mums from seed.
Try your hand at growing chrysanthemum seeds. While it’s not a foolproof way to get the exact color garden mum you want, you can save some money and enjoy the journey of starting mum seeds. Garden mums cross-pollinate freely, so when you’re growing chrysanthemum seeds, you’re never certain what type of flower will result. Commercially, garden mums are most often started from cuttings, which ensures growers get the exact type of flower in the precise color they want.
Mum seeds are remarkably small. There are roughly 45,000 seeds per ounce. When handling chrysanthemum seeds use care. One sneeze or breeze through a window could send thousands of seeds into oblivion. Chrysanthemum seeds need up to 16 weeks to flower when grown from seed. Most growers agree that starting seeds indoors—before all chances of frost have passed—is the best choice.
Fill small germination pots with sterile seed starting mix. Level it, and give it a quick splash of water so it’s moist. To make sowing easier, try pinching a few mum seeds between your thumb and forefinger. Slowly roll them back and forth so just a few drop to soil at a time, instead of a large clump.
Chrysanthemum seeds need some light to germinate. Barely cover them with more seed starting mix. Apply it very gently and in a thin layer, so some light can reach seeds. Use a spray bottle to spritz the top layer of soil mix you just added. Press the top of the pots gently to make sure that seeds and soil mix are touching. That contact is key to successful germination.
Provide some warmth in your seed starting area. Mum seeds like a toasty 70 degrees F to germinate. You might want to use a root zone heating mat to warm soil and improve germination rates. Keep the soil moist during germination using a spray bottle to mist the soil surface. If you use a heating mat, check soil more frequently for drying out.
You’ll need bright light to produce stocky seedlings. Place seed trays near bright south or west windows, or provide supplemental light using fluorescent grow lights. Suspend lights 12 to 15 inches above seed trays. Keep soil evenly moist until mum seeds sprout, which should occur in 10 to 15 days.
Thin seedlings shortly after they have their first set of true leaves. Snip the stem of the seedlings you aren’t keeping. Don’t pull them from soil or you risk disturbing the roots of the mum seedlings you want. Transplant seedlings into small pots when they’re a few inches high. Harden off seedlings outdoors, gradually getting them used to outdoor growing conditions.
It is possible to sow chrysanthemum seeds directly into planting beds outdoors. Just be sure to keep soil evenly moist, which is the trickiest part. Sow seeds after all danger of frost has passed in spring.