How to grow Osteospermum from seed?

Osteospermums are a fantastic addition to the summer garden, and yet they are relatively new to most gardeners and were almost unheard of 25 years ago! While they are technically half-hardy perennials or subshrubs they are generally grown as annuals even though they will quite happily overwinter in a bright, frost-free environment. Be that as it may hardier species are available to purchase (Osteospermum 'Lady Leitrim' and 'Paleface') and these can tolerate temperatures as low as -13 degrees Celsius!

How to grow Osteospermum from seed -
Native to Africa and the southwestern Arabian Peninsula, these large showy, daisy-like flowers are available in a wide range of stunning colours white, cream, pink, purple, mauve to yellow and even a deliciously hot red.

A few cultivars are even more ornamented with spooned-shape ends to the petals such as "Pink Whirls". Many of the species will have a second flowering over the late summer, stimulated by the cooler night temperatures. The hardy species will flower profusely spring, but unlike their less hardy cousins will not produce a second flush of flowers later on in the year.

As gorgeous as osteospermums are they can be expensive to buy, however they can be grown from seed. Just be aware that if you collect your own seed the resulting seedlings are unlikely to grow true to the parent plants. You can either propagate from these vegetatively, or purchase pre-packed seed from a reputable company.

Osteospermum seed?-
You can sow osteospermum seed in the early spring. Fill a modular seed tray with a good quality free-draining compost such as John Innes 'Seed and Cutting'.

Sow the seed at a rate of one seed per module and then cover with a light sprinkling of perlite or vermiculite. This is because osteospermum seeds require light for germination.

Water gently using a can with a soft rose, or carefully dunk the tray into a container of water allowing the water to naturally rise through the soil. Do not submerge the tray.

Allow the tray to drain and then seal inside a clear polythene bag. Place on a warm bright windowsill but out of direct sunlight. You can expect the seedlings to emerge after only 10-15 days  at 15-18C at which point they can be removed from the bag. keep the tray on the windowsill and allow the compost to remain moist but not waterlogged.

 Osteospermum seedlings -
Once the seedlings have rooted well in their module they can be lifted and potted on into 3 inch pots and grow on in cooler conditions.

They will need to be gradually acclimatized to outdoor conditions for 10-15 days before planting out into their permanent position but only on all threat of frost has passed.

They will do best in a warm sunny spot on light, well drained soil. If you are planting them in groups, grow them 12 inches apart.

Osteospermum file is licensed under the Creative Commons Attribution-ShareAlike 3.0 License.

For related articles click onto the following link:
How to Grow Osteospermum from Seed

No comments: