Creating Colour Indoors – sow coleus this winter!

Life’s too short not be gardening year-round! And one of the ways you can have fun with growing over the cooler months is by purchasing a packet of coleus seed. Few plants offer the same vibrant foliage or the sheer range of leaf size, shape, and pattern as semi-shade-loving coleus. What’s more, these bright beauties are so simple to germinate, grow, and foster.

Coleus hails from tropical regions of Southeast Asia, and belongs to the mint (Lamiaceae) family (take a close look at the leaves on some coleus, and their shape is the clue to the connection). Coleus differs from mint, however, in its foliage displays vibrant reds, yellows, and rich purples and greens. Sometimes, leaves are a single colour, at other times they are patterned with distinct colour breaks. The combo of colour and patterns can seem endless – which is why these plants are so much fun to grow. Don’t expect too much from a coleus flower, however. The blooms on these gorgeous plants are small and insignificant.

Germinating, transplanting, and growing coleus is entirely possible over the winter, when you know how to go about it. What’s even better, these little gems are fast growing, so if you sow their seed now, they’ll be the perfect size for giving as Christmas gifts, and for sales tables at summer fund-raising fairs.

If you need any more encouragement to have fun with these fab ornamentals, how about this: any seedlings, raised indoors during the cooler months, have the potential to become ‘leggy.’ (In the gardening world, it’s the term used for plants that become tall and spindly, rather than full and bushy.) It’s a problem which develops when plants don’t have access to enough light, or when they are accessing their light from just one direction, such as through a window). But here’s the thing – coleus thrive on being ‘pinched  out.’ Pinching out is the simple art of nipping off the central growing tip of a stem – something which causes the plant to grow in multiple directions. So should your coleus seedling start to look leggy, you know what to do!

Another plus for winter coleus seed-raising is this: unless you choose a specific sun-tolerant variety of coleus, you can rest easy in the knowledge these bright plants actually prefer light shade. Which means you shouldn’t be afraid of keeping them in a warm, but not necessarily bright, part of the house while it’s still too cold for them to be outdoors. In fact, popping coleus onto a sunny window ledge isn’t recommended, as bright light can scorch their foliage. Coleus do enjoy humidity, though. So while your home is toasty warm inside, remember to place your potted coleus plants on saucers or trays of water to help create a moist environment.

Once you have your coleus seed (and for variety, Egmont Seed is a great source), sow them into a container of fine, damp, seed raising mix (sieve the mix, if necessary, to remove any rough pieces). Scatter vermiculite on top, sparingly, to assist with germination, and pop your seeds into your hot water cupboard where they will be warm (don’t forget to spray them, daily, with water to keep them damp). As soon as the seeds have germinated, take the container out of the cupboard, and place it in an indoor spot that is warm but which doesn’t receive direct sunlight (coleus plants prefer temperatures between 15-24°C).

Prick out the tiny seedlings into individual pots of potting mix once they have their first true leaves (leaves which resemble the leaves on an adult coleus). The sooner you can do this, the more successful the transplanting will be (use tweezers if it makes the process easier).

As your coleus grow, keep the potting mix damp, but not moist. Turn the plants daily so they receive light from all sides. When the plants have been in their individual pots for 3 weeks, feed them, according to the instructions that come with the product, with a balanced, water-soluble fertilizer. Pinch out the growing tips once the plants are 15cm high, to encourage bushing.

Keep your coleus as gorgeous potted plants, or once spring arrives, those living in warm regions can plant their coleus outdoors in a semi shaded spot. Those in cooler parts of the country can plant their coleus outdoors, in a similar spot, once summer arrives. Coleus are very frost tender, so although they are actually perennials, they are generally treated as annuals.

Coleus are such easy, fun plants to grow, so as well as sowing their seed yourself, pop some in for the grandchildren and the younger people in your life. We wish you well with this fabulous winter gardening project!