Keeping up with kūmara

Like potatoes, kūmara would have to be one of those vegetables that is a pretty regular feature in my pantry. They’re versatile (there’s a long list of dishes I can add kūmara to) and they taste great! 

I’ve enjoyed growing kūmara in my garden for some time but we’ve never sold it at the nursery. So I’m pretty excited to announce that you can now purchase kūmara seedlings from our stockists or from our online shop.

Our regular-sized bundles have four seedlings and our bulk bundles contain 10 seedlings. Not sure how many you’ll need? Well, this is how I work out how many to plant. If all goes well with my kūmara growing I expect each plant to produce around a bucket of tubers. So, a regular-sized bundle should produce around three to four buckets of kūmara.

Once you’ve worked out how many seedlings you need, the next job is to find the right spot to plant them. Each seedling needs to be planted around 50cm to 1m from the next, so you do need a bit of space to have a kūmara crop.

Kūmara like a pH of 6.0 to 6.5. If you’re not sure what pH your soil is, you can buy a simple to use pH kit from your local garden centre. If the pH isn’t high enough add a bit of lime to sweeten the soil. Don’t add too much, or any if you don’t need it, because too much lime will mean you end up with small kūmara.

Now, it’s important that you raise a mound of soft soil for the kūmara to spread out in. Cultivate your soil with a rake and then mound it up in to a hill around 40cm high.

Next make a small trench approximately 5cm deep and lay the seedling so that the root is lying in the trench parallel to the top of the soil, rather than pushing the root down like you might with another vegetable. But make sure you bend the seedling so the leaves are sticking out of the top of the soil ( a J shape). This will ensure the plant’s roots (via the leaves) get plenty of warmth from the sun.

Water gently around the plant – it’s important not to water forcefully as this might make the mound flatten out or the plant roll off the mound. Do this for the first few days and then ensure they get some water weekly. Depending on what summer is like this year you may not need to do any extra watering at all. But if it’s hot and dry keep an eye on things and water at least weekly.

Generally, try to lift the runners so they don’t put roots into the ground. The runners are the shoots that run along the ground off the main plant – much like strawberries. Lifting them off the ground will stop them from putting roots down and wasting energy that could go into forming tubers.

However, if you want to increase the size of your plot you could let a couple of runners put roots down and then cut them off and replant them.

Kūmara need at least four months of sunshine before they are ready to harvest. So, around February, March or April is when you can expect to start digging into your crop. It’s important you harvest before the first frost. Around this time the leaves may start to yellow, which is a sign they’re ready. But if you live up north this probably won’t happen. So, around four months after you’ve planted put your hand in the ground and gently see if the kūmara feels ready – this is called tickling!

When you know they’re ready, harvest very gently. Broken kūmara won’t store. You may have to really follow the plant around with your hands under the soil to ensure they come out without breaking.

If you want to store them for a long time it’s important they are cured properly. This is when the starch is converted to sugar and a second skin is created that allows them to last longer in storage. If they’re cured well they can last for up to a year in storage. The professionals use temperature and humidity controlled storage sheds to do this but you can try and replicate this in a few ways.

Once they’re out of the ground keep them at a temperature of around 25-30 degrees Celsius with high humidity (around 90%) for at least seven days – including at night. If you need to increase the humidity, try putting them in a box and covering with a blanket or plastic with some holes in it. While you want it humid and hot, you want air circulating so they don’t go mouldy. When they’re cured the skin should be harder and any bruises or cuts should be dry and clean looking.

Then store them in a dark place around 14 degrees Celsius. You can also wrap each kūmara in newspaper or brown paper bags – this will help provide air circulation and prevent them from rotting. Keep an eye on them and remove them gently when you want to use them.

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