Your Guide to Dahlia Growing

Your tubers are packed in paper bags in wood shavings inside a compostable mailer or card box. Very carefully, take your tubers out of their paper bags and put them in a cardboard box under a layer of potting mix or dampened sawdust. Be careful not to damage the ‘eye’ as this is delicate and can be easily knocked off once it starts growing. Don’t worry if the eyes on your tubers have not started developing when you receive them; some varieties are slower than others. 

Place your cardboard box of unpacked dahlias in a cool dry place until planting time. Crack the lid a little to allow some airflow. Regularly check your tubers to ensure they are not rotting or drying out. Discard any rotten tubers so the rot doesn’t spread to others in your box.

You may notice a white powder on the end of your tubers. This is wood ash and helps the cut heal as well as having anti-bacterial and anti-mould properties.

Tuber sizes vary depending on the variety and the season. On our flower farm, we plant anything the size of an AA battery or larger. A bigger tuber doesn't equal a bigger plant. In fact, smaller tubers survive early warm weather better as they are faster to put down roots than the big tubers.

Tubers are inspected 2 to 3 times before shipping to ensure there is at least 1 eye. Please allow up to 5-6 weeks after planting for the tuber to grow. Some are slower to sprout (especially the dinner plate ones).

If you are concerned about your tubers when they arrive, please email us with photos at rebecca@starlingflowers.com.au within the first 2 days. In the case of a problem, we will send a refund. If you can't see an eye and are unsure, contact us and we will make a 'watch and wait' note on your order. 

After this time, the tubers are your responsibility as we can't monitor storage, planting or growing conditions. While dahlias are pretty tough, sometimes they do get eaten by soil borne worms, snails, birds or dehydrate / rot through water absence / excess. This is part of gardening and while it's not necessarily something you can control, learning about how dahlias grow best in your conditions will give you better and better results each year. It can take a few attempts to perfect your approach. 

How to Plant your Tubers

Growing from tubers is the easiest and most popular way to grow dahlias. Plant outside after all risk of frost has passed which is October/November for cool and temperate zones.

First bang a stake into the ground where you will plant your dahlia tuber. With the 'eye' closest to the stake, plant your tuber horizontally with the tail end slightly slanting down. Don't forget to label it. We write on the tuber in permanent marker and also tie a label to the stake. Cover your tuber with 10cm of soil. Dahlias are heavy feeders so you could add compost to your soil before planting. When the leaves emerge, we spray a liquid fertiliser every 2 weeks until flowering starts.

Increasing your plant numbers

You can plant your tubers in pots when you receive them and take cuttings to increase your plant numbers. Just pot up those cuttings and let them develop roots. When it’s time to put the tubers in the ground, plant them in the normal way.

It is great fun to also grow dahlias from seed although you will struggle to predict the outcome. This is because dahlias are octoploids, meaning they have eight sets of chromosomes rather than our two sets. That creates lots of opportunity for variation but is also the reason why there are so many different colours and forms of dahlia flowers.

Tips for Growing Beautiful Dahlias

If you want your plant to produce multiple blooms, you must "pinch" or cut back the plant early on, when it has reached about 20cm tall. Find the centre stalk, count down about 1 to 2 sets of leaves and make a cut with clean secateurs, removing the top 5 cm of the central stalk. This tells the plant to "branch out" and put its energy into creating more blooms.

When you cut those first few stems, go low. It is better to sacrifice a few side buds in order to get longer, more usable stems. In any case, the plant will become bushier and will send up more flowering stems for the rest of the season than it would otherwise have done.

Always support your dahlias. There are lots of different methods. We tie ours to individual stakes as we live in a very windy place. Then, mid-season, we corral the whole plant using twine, sweeping up the side branches and tying it to the stake. This ensures all the stems stay straight and stops the plant from toppling over.

Thank you

We really appreciate your support and hope you have a fantastic dahlia growing season. We love our dahlias and hope you enjoy them in your garden as much as we do. For more information, sign up to our newsletter on our website. We send out growing tips and advice as the season progresses.

Happy Growing!

Rebecca