with Ted Smith
Welcome back my waterlogged friends. Considering the start to this year’s growing season I’m thinking that perhaps we should be talking about growing rice or water cress instead of crops like asparagus that hate wet feet. I suppose if we just wait a week or two we’ll likely be in drought conditions again so we might as well just laugh and roll with it.
In this case, rolling with it means finishing up our look at growing the world’s favourite perennial vegetable. As we’ve discussed over the past couple of columns, growing asparagus is not that difficult as long as you take the time to do things properly right from the start. A small investment in time and effort now will yield delicious results for a couple of decades or more.
At the end of last week’s Garden Gossip column we were discussing the issue of cutting down your asparagus ferns once the harvest window has passed. Many gardeners do this for aesthetics, not realizing just how important those ferns are to future years’ production. Green plants rely on sunlight for their energy. For our purposes, consider an asparagus plant to be like a solar energy collecting system. The roots of the plant represent the storage batteries while the leaves (ferns) play the role of solar panels. If you take the solar panels out of a solar collection system the batteries cannot charge. The exact same is true of your asparagus plants. If you cut the ferns down you are effectively starving the roots of energy and your asparagus bed will be very short lived. Leaving the ferns on into the winter can also serve another function. The dead stalks will collect blowing snow over the course of the winter which will effectively insulate your asparagus roots and help protect them from frost heaves. A quick cleanup right after the snow melts in the spring is your best strategy for cleaning the asparagus bed. This is also a great time to meticulously remove any tiny weeds that are germinating in the spring warmth and cut off that potential problem before it gets a foothold.
Fortunately, there are not a lot of problems that will affect your well established asparagus patch but there are a few things to be on the lookout for. Asparagus beetles are probably the greatest threat to local asparagus patches. There are two types of asparagus beetle and they are both found on Manitoulin. If you plant asparagus, rest assured that they will eventually find you. Once they do you will likely have new friends for life. Asparagus beetles are small elongated beetles that are about four or five millimeters long. Both varieties of asparagus beetle are very colourful and spotted. They will be easy to see on your plants and usually show up in late spring. While there are some organic treatments for asparagus beetles, the best approach is simply meticulous hand picking and removal of the beetles, their eggs and the feeding larva. The eggs are usually deposited near the tips of spears and are clusters of small black specks on short stalks. They can be rubbed off before they hatch. The larva are small greyish grubs that are often seen in great numbers. They can easily be picked or knocked off the spears. Only vigilance will prevent a serious infestation. Left unchecked, asparagus beetles and their larva can decimate a stand of asparagus pretty quickly. Many other lesser asparagus pests exist but they are mostly capable of inflicting limited damage.
Other problems often seen in asparagus patches are crown rot, rust, and purple spot. These problems are generally fungal in nature and good garden sanitation coupled with excellent airflow will be your best preventative measures. One practice that is used by many organic growers is the spreading of pickling salt (never iodized table salt) amongst your asparagus spears. Recently this practice has fallen into disfavour with many growers but it does seem to be effective at boosting the asparagus plant’s immune system which is critical for fighting off diseases. Pickling salt has another benefit in that it has no negative effect on salt tolerant asparagus plants but it is highly toxic to most competing weeds in the asparagus patch.
The last consideration when growing asparagus is choosing the variety to go with. All male hybrids are available and produce remarkably higher yields than heirloom varieties. You can also grow purple asparagus which is larger, sweeter and more tender than most green varieties. The “white” asparagus that is often seen in stores is simply green asparagus grown in the absence of sunlight. You can do this by banking soil around the growing spears much as you would for leeks.
And that, my friends, is everything you need to know to grow asparagus. Enjoy!
