How To Grow Mums (Chrysanthemum) From Seed
Mums (Chrysanthemum flowers) can grow rapidly from seeds in just 10 to 15 days.
However, seeds must be planted at the right time of the year and kept under appropriate conditions to perform their best.
Mums take up to four months to flower from seed.
Therefore, the best time to start with seeds is by sowing them indoors in early spring.
Start the seeds about eight weeks before the last spring frost, which is approximately mid-February.
The seeds can also be started outdoors, from after the last spring frost until two months before the first autumn frost.
But, the seeds germinate less reliably when sown outdoors due to temperature and moisture changes in soil.
Planting Chrysanthemum seeds indoor:
- A warm room (70-75 degrees F) and light exposure is key to successfully germinating mum seeds.
- Sow the seeds by lightly pressing them onto the surface of the soil.
- Spread a very thin layer of soil on top so they are covered but still somewhat exposed to the light.
- Mist the surface with a spray bottle and gently tamp it down to increase contact with the seeds.
- Keep the top 1 to 2 inches of the soil moderately moist during the germination process using a spray bottle.
- If the room receives less than six hours of bright, natural sunlight each day, suspend a fluorescent grow lamp 12 to 15 inches above the pots to supplement the available light.
- The temperatures should stay reliably above 70-75 degrees Fahrenheit. If not, warm the pots with a heating coil or propagation mat and keep them covered with plastic wrap.
- Closely monitor the moisture level in the soil when using a heating coil or fluorescent lamp because artificial heat will cause it to dry out faster.
- Seedlings emerge in 10-21 days.
- Once sprouted, the emergent seedlings must be thinned out promptly to prevent overcrowding.
- Remove the spindliest seedlings from each pot and leave the most robust one.
- Water at the base of the seedlings, taking care not to splash water onto the leaves.
- Seedlings do not need much fertilizer, feed when they are 3-4 weeks old using a starter solution (half strength of a complete indoor houseplant food) according to manufacturer’s directions.
- If you are growing in small cells, you may need to transplant the seedlings to 3 or 4 inch pots when seedlings have at least 2 pairs of true leaves before transplanting into the garden so they have enough room to develop strong roots.
- Before planting in the garden, seedling plants need to be “hardened off”.
- Leave them out for a few hours each day, gradually increasing the length of time over the course of two weeks.
- Accustom young plants to outdoor conditions by moving them to a sheltered place outside for a week. Be sure to protect them from wind and hot sun at first. If frost threatens at night bring containers indoors, then take them out again in the morning. This hardening off process toughens the plant’s cell structure and reduces transplant shock and scalding.
- Then, transplant them 12 inches apart in a sunny bed with rich, fast-draining soil once the soil warms up.
Planting in the Garden:
- Select a location in full sun with good rich moist organic soil.
- Prepare the bed by turning the soil under to a depth of 6-12 inches removing any debris, and raking as level as possible.
- The addition of leaf mold, compost or well-rotted manure can add a benefit.
- Plant on a cloudy day or in late afternoon to reduce transplant shock.
- Dig a hole for each plant large enough to accommodate the root ball.
- Unpot the plant and gently loosen the root ball with your hands to encourage good root growth.
- Place the top of the root ball even with the level of the surrounding soil. Fill with soil to the top of the root ball. Press the soil down firmly with your hand.
- Use the plant tag as a location marker.
- Thoroughly water and apply a light mulch layer on top of the soil (1-2 inches) to conserve water and reduce weeds
Good luck with your mums!