Growing Dahlias from seed

Summer light fallling on Dahlias

It’s clear that when the dahlias arrive in the garden, so does summer. And after the froth and fizz of spring beauties like nigella, Iceland poppies, ranunculus and sweet peas, the appearance of the sturdy, almost fleshy dahlia marks a real change in the tone of garden. It is incredible that these floral beasts grow so quickly from an ugly, shrivelled and unpromising tuber.

For the last few years I have been supplementing my expensive dahlia bulbs with dahlias grown from seed. Dahlia seed is CHEAP - usually less than $5 for a packet of 25-50 seeds. Seeds are more of a gamble than tubers - you are not certain what colours or exact type (doubles, anemones, singles etc) you might get, but compare the price of seed with paying $10-$20 PER BULB, and you quickly see the attraction of giving dahlia seeds a go.

Last season I grew Unwins mix, and got a great variety of colours and shapes. By mid-summer the seed-planted dahlias and bulb-planted dahlias were indistinguishable in terms of height, health and bloom production. Like Dahlias grown from tuber, at the end of the growing season, the seed raised plants can be pulled up and tubers saved for the following spring. Over the summer growing period, I marked the dahlia varieties and colours I really liked (tied a piece of string around the base of their stems) and when I dug up the tubers I only kept those marked ones, ditching the rest. Composting dahlia tubers is not something I usually do as the tubers are so expensive, but when you are paying mere cents for each plant grown from seed, you can ruthlessly discard anything less than fabulous.

Although you can’t really choose the exact colour you want when growing from seed, many seed companies do offer set colourways, allowing you to choose whether you want lots of bright colours or a more pastel palette. This year I am growing both Summer Bouquet and Sunny Reggae from Jardin de Fleur. Almost all of the Summer Bouquet successfully germinated and transplanted, but I have not had much luck with Sunny Reggae. Planted from seed in early August into paper pots (kept in the greenhouse) and planted out into the garden first week of September, these babies began blooming early November. Fast! They are still fairly small plants, but if they grow anything like last year, they’ll be at full height by Christmas and keep on blooming right through until late May or our first frost.

So if you want lots of Dahlias, are not too fussy about the exact type of colour, you can easily grow 30, 40 or 50 plants plus from less than $10 worth of seeds. Worth a shot.