30/09/2026
There really isnât one spacing that fits every dahlia garden.
At Bay Dahlias, our spacing depends on whether we are assessing a seedling or growing an established named variety.
For our 2nd- and 3rd-year seedlings, we plant approximately 1 foot (30 cm) apart, with around 18 inches (45 cm) between the rows.
Why give the seedlings a little more room?
Because theyâre still under assessment. We want to see their true potential â plant habit, vigour, stem production, flower form and overall performance â without crowding becoming too much of a limiting factor. These are the years when weâre deciding whether a seedling deserves another season.
For our named varieties, we grow much tighter: approximately 1 foot Ă 1 foot, with three plants
across the bed.
This works for us because weâre no longer trying to discover what those plants are capable of â we already know them. Our priority becomes making the most of the growing space we have. Growing them closely also creates a more interconnected canopy, although we still stake and support the plants rather than relying on neighbouring dahlias alone.
And when do we plant?
For us, late October is still the safer general planting window. But with the number of tubers we have to get into the ground, we simply canât plant everything at once.
So we stagger our planting.
Some of our pre-sprouted tubers start going into the ground from late September, provided soil conditions and the short-range frost forecast are suitable. We continue planting progressively through spring, sometimes right through to mid-December.
Our soil is already measuring above 15°C, which gives us another useful piece of information when deciding when to start.
Weâre also growing through a strong El NiĂąo this season. Current NZ climate guidance expects its influence to continue through spring and into summer, but that doesnât mean frost risk disappears â cold outbreaks can still occur. So we use the seasonal outlook as context, while the actual soil conditions and local weather forecast make the final call.
For us, growing dahlias isnât about following
one calendar date.
Watch the soil. Watch the weather. Know your land.
And plant accordingly
