Baby, it's cold outside - down here in the Southern Hemisphere it's the time of year for crackling fireplaces and slow cooking, and there is no better time for planning the coming season's edible garden. If you're tempted to try growing Asparagus, read on.
Home-grown asparagus isn't just a crop, it's a relationship. An asparagus bed can last for up to 20 years so it's worthwhile doing a bit of research before you make your bed and have them lay in it. One of the first issues that would-be asparagus growers come up against is the complicated sex life of the plant.
You see unlike most plants, asparagus are gendered and, like us, the female plants produce the fruit. Bright red berries on the ferny foliage denote a female plant. Here at Country Trading, we are often asked 'how do I tell the difference between young male and female plants?' and, 'do I need one of each?'
Until the plant produces ferns at the end of the growing season, you can't tell them apart but the good news is you don't need one of each. We don't eat the fruit of asparagus, we eat the new shoots - and both sexes produce these.
The fruit is a bit of a nuisance. Male plants start producing spears earlier in the season and produce between 10 - 20% more shoots than the female plants. Probably because they don't have to expend all that energy needed to raise the kids! The berries from the female plants can also self-seed in the bed, clogging things up.
Asparagus is one of the oldest vegetables in human cultivation and so over the centuries growers and breeders have kept a keen eye on it and selected varieties for different characteristics including colour, longevity, size, disease resistance, climatic tolerance and even sexual orientation. In the 1960's Professor Howard Ellison from Rutger State University, New Jersey discovered some hermaphrodite asparagus plants which he self-pollinated and through further breeding created hybrid varieties that produced all-male offspring. These varieties often have "Jersey" in the name and are marketed as all-male producing.
To confuse matters further, home gardeners can also choose from a range of modern hybrid varieties resulting from arranged marriages. These hybrids still produce both male and female plants but may outperform their open-pollinated heirloom cousins in certain departments like disease resistance and longevity.
All of this can make choosing a variety of asparagus to grow in your garden quite baffling. Is that fancy violet Italian renaissance model a good idea or should you opt for plain American Mary Washington? Is a same-sex marriage from New Jersey going to be any good or should you go for the performance-enhanced Pacific 2000 hybrid, with girls included but bred for New Zealand conditions?
Asparagus eh? Who would have guessed it was such a hotbed. I'm all for open-pollinated varieties so folks can save and sow the seeds again and again - but when it comes to asparagus - how many beds are you going to have? So in this case, I opt for modern hybrids. The Pacific 2000 is such a good performer that I don't mind the odd girl in there bringing down the average and I know it does well in our growing conditions. While I have nothing against the all-male hybrids I'm not sure how well they perform here in the long run.
Some tips on Growing Asparagus
- The common myth that a bucket of saltwater will do wonders for your asparagus patch is just that, a myth. They may be salt-tolerant but I can vouch that a bucket of alpaca pooh or any other well-rotted manure will be more welcomed. Just because asparagus is salt tolerant doesn't mean it loves it.
- If you're growing asparagus from seed, grow the plants in individual pots for the first season and then plant them as one-year-old crowns the following spring when the soil warms up.
- Prepare your asparagus bed well in advance of planting. It's going to be there for a while so it is worth putting time in upfront to get it right. Asparagus likes good, free-draining soil and plenty of well-rotted compost and manure. It is a good idea to dig your row around 30cm deep and the same width, then fill the bottom with a mixture of sandy soil, compost and well-rotted manure.
- Asparagus likes a slightly acidic soil so if your soil is very acidic add a few handfuls of lime to make it more asparagus-friendly. If it is more alkaline add some garden sulphur and mix it in well before you plant your crowns.
- Place your crowns in the trench in two rows, spacing each crown 20 cm apart and covering them up until the trench is around 10 cm from the top with more of the soil and compost mix. In the first winter fill in the rest of the trench.
- Leave your bed the first year without picking it. It is the second spring of growing that you can start picking and you'll get a good 3 or 4 weeks of picking spears before they start to run to ferns. From your third year onwards, you should get a harvest period of around 7-8 weeks from your bed.
- A well-tended asparagus crown from modern hybrid should produce 450g (a pound) of asparagus a season so allow 4-6 crowns per person depending on their love for the stuff. If you're growing the older heirloom varieties allow more crowns per person.
- Keep the watering up during the growing season and pick daily as it becomes fibrous if left to grow too big.
- Eat them every day too, as once picked they start losing their natural sugars, this is why growing your own asparagus is so rewarding - fresh is definitely best! Purple asparagus is sweeter and more tender than the green varieties and is good to eat raw, sliced in salads
- White asparagus can be grown by covering purple asparagus with black plastic or mounding it with soil. It is very sweet and popular in Europe.
- You will know when to stop cutting the spears as they start getting spindly. Don't over cut them - leave the spears to go to ferns as these provide food for the crowns to produce next years crop.
- When the ferns start to die off in autumn cut them back to just above ground level and cover them with a good layer of compost for the winter.
Now all you have to do is make the hollandaise!