As many of you are aware, it’s recommended we don't plant until labour weekend due to frost, rain and unexpected cold nights and hail, all which can kill early sprouting tubers. This leaves us with a problem since we often have around two or three months between buying and planting and you cant leave the tubers bagged or they either rot or dry out. For those who want to know what to do between receiving dahlias and planting out, here’s what I usually do:
( my "On a budget" version, tweak it to fit your circumstances. )
The first question to ask yourself is - Are you potting to store until planting, or are you potting to on grow for cuttings? They have different requirements and need different methods.
POTTING FOR CUTTINGS: see photo one
The two biggest threats to tubers prior to planting are dehydration and rot - finding the balance can be tricky and it’s really just a case of checking the feel of the soil regularly.
Because I grow for cuttings, labeling is the first step. Using a waterproof marker on the tuber as well as on a tag and then recorded on my online note book ( I use numbers instead of names ) before being potted in boxes and trays of cheapest potting mix or old soil from my pots. Avoid using anything with lots of fertiliser, it’s not needed and can actually be harmful at this stage.
They then get moved to where ever is warm and humid - at the moment that’s my greenhouse with the door open for air flow. Warmth, humidity and air flow are ESSENTIAL . Warmth to get them started, humidity to stop them drying out and airflow stop them getting mouldy. I constantly check the soil and conditions, and watch for infestation of ants and slaters. Please note that store bought tubers are often imported so are likely sprouting when you buy them. I remove the shoots before potting so that they resprout with multiple shoots ( see #cuttings and #tubertipsandtricks for more information on this.
POTTING TO STORE UNTIL PLANTING:
When you pot to store , you keep them cool and lightly damp ( but not wet ) and that stops them dehydrating or activating.
In past years I’ve used banana boxes with potting mix on trays in my garage ( the boxes go soft so you need something under them for moving them )