Meanwhile, inside I'm admiring the progress of my greening potatoes on the windowsill. The brown, earth covered ones at the right are a few of the seed potatoes I have bought. The green ones at the left - which have been on the windowsill for longer - are ones from the supermarket which went green before we could eat them. I have lots more seed potatoes, but I might stagger the planting over a couple of months, although I'm not sure it will make much difference to when the individual plants mature.
Now I know you're not supposed to plant supermarket potatoes in case of disease, but I'm going to give it a go and put them in pots so they're excluded from the general garden. I dithered and dithered about whether to get big cheap black plastic pots or to go for planter bags, and in the end - after thinking about this for literally weeks, which is a long time to be thinking about what to plant potatoes in! - I have ordered 6 x 45 litre planter bags. I thought you could only put one seed potato per bag, and I was having visions of my backyard being filled entirely with pots, but I've since learnt that you can put several seed potatoes in each pot/bag which will save me a lot of space and money.
The rest of the potatoes - my certified disease free batch - will be planted in the garden using a No-Dig method. For this I've referred to Peter Cundall's The Practical Australian Gardener, where he tells me it goes like this from the bottom up:
- Green manure crop, flattened/lawn/mown weeds/bare earth
- Seed potatoes, 30cm apart and rows 60cm apart
- Straw material fluffed up and pile at least 50 cm high
- Water thoroughly
- Sprinkle blood and bone and added potash (10%), one handful per square meter
- Animal manure - several shovelfuls per square meter
- More water
It's important, I've read, to make sure all light is excluded from the seed tubers, and if the straw seems to flatten down too much over a few weeks (to less than 15cm) then you can top it up. If the tubers have sprouted through the straw already then just pile your straw around them but not over them.
I've also been doing some reading on whether or not to cut the tubers. I found an interesting document here. It's not all relevant to the home gardener - for example I'm not going to pile my 800g of seed potatoes more than six feet deep! - but it's good to know that each seed tuber or piece should be between 1.5-2 ounces (that's about 45-60g, or the size of a hen's egg), and that higher yields are generally associated with larger seed pieces. In short, in my little bag of seed potatoes I'm better off leaving them alone rather than being greedy and trying to double my number of plants with the aid of a sharp knife (but, if you do decide to cut your tubers, you need to let them dry out again afterwards for a few days.)
So, there you go! I've never really done much research on any of my vegetables before I planted them until now, but I'm hoping it will pay off in my potato yields. We'll just have to wait and see!
Patience, Grasshopper, patience...