Planting Dahlia Tubers

If you have just bought some new tubers, they can be planted out in the garden straight from the packet. Or if you want earlier flowers, start them off in pots of multi-purpose compost, then plant out later. You can also grow them in 7 inch pots, even larger if possible.

If you have removed dahlias from storage, carefully shake as much soil off as possible, watching for the yellow slug eggs which have overwintered with them (I haven't found any yet, but I will show you what they look like if I do).

Dahlias are easy to grow and you can just dig a hole and put them in. Single tubers can be laid flat, so that the neck is about five inches below soil level (They can be planted much shallower than this, but because they love water, planting them deeper is best. It is also best if you want to overwinter them in the ground. Frost very rarely gets down to this level, especially if the ground receives some sun during the day in winter).

WATER THEM FIRST
If you are planting tubers surrounded by dry soil, make sure it is moist first. Always do this with plants, because if they are dry when planted they might remain this way all season.

What I often do is give them all a light drink whilst still in storage position. This gives them a slightly better start. It also hatches the slug eggs so that these pests can be easier dealt with. However, it is still a little bit early for this. Best done in a week or two when it feels more like spring.

GETTING BETTER RESULTS
Dig a hole about 30 centimeters (12 inches) deep.

Add some multi-purpose compost to hold the water (do not use raw peat; it is too acid). They cannot get too much compost.

I like to add about an egg-cup full of bonemeal to the bottom of the hole to act as a feed. If you can't get bonemeal, don't worry, the compost should contain enough feed to get them started. Give them a soluble foliar feed as soon as they break through.

Mix the whole lot together.

Add a few slug pellets just in case.

Lay out the tuber as best you can, vertically or horizontally. Be careful not to damage it. The neck of the tuber should be at least 20 centimeters (4 inches) below the surface.

I add some 'Derris Dust' to keep millipedes and wireworms at bay. This is beneficial but not necessary.

Work some loose soil around the tubers as best you can.

SPEEDING UP THE PROCESS
Cover the neck of the tuber (from where the new shoots will come) with about an inch-and-a-half of soil, just enough to keep the frost off. There should now be about 15 centimeters of hole above the neck.

Why not fill in the hole completely?

Well, you can fill the hole in completely, but this way the sun warms the tuber quicker and speeds germination. It takes quite a bit longer at this time of year for the soil to warm up lower down. And if it gets a bit frosty, you can always scrape some more soil over them for protection.

That's all there is to it. They should be up in a few weeks, depending upon the weather. Watch out for slugs attacking the new shoots as they break through the soil surface.