Growing and harvesting asparagus – March 2016
Michele and I recently celebrated our 40th wedding anniversary with a holiday in Madeira. Not having had a honeymoon, we pushed the boat out with a four star hotel and junior suite. This of course brought us into contact with posh vegetables so let’s look at growing asparagus.
This is a luxury crop as it’s a perennial plant that can take up a lot of space in the vegetable plot and only has a cropping season of about four to six weeks. Asparagus needs well-drained deep soil, its roots can extend up to one metre in the ground, so for this reason a raised bed can be beneficial. The plants can be productive for 20 years or more so it’s worth spending some time on bed preparation.
It takes three years for the plants to mature enough for a full crop to be taken. The soil should be free of perennial weeds and deeply dug with compost or manure well-incorporated. It is possible to grow asparagus from seed but this extends the length of time to cropping. Usual practice is in early spring to dig out a trench to 200mm deep and 300 wide and plant one year old crowns. Mound up the soil inside the trench so that the crowns lie over the mound. They are a delicate plant so sift soil over them to a depth of 100mm. The remaining garden soil can then be added. Do not tread down.
Don’t take any spears in the first year, feed the plants by applying a top dressing of general garden fertiliser. Support the foliage if required, the frond-like leaves create energy through photosynthesis, feeding the plants and creating healthy strong roots which in turn creates healthy strong spears. Once the foliage turns yellow they can be cut down. In the second year after planting, you can harvest no more than one or two shoots from each plant and continue to feed the plants.
Full harvesting starts in the third year. When the spears are 100mm above ground, sever them 75mm underground using a serrated knife, cut every spear this size. If you do not have enough for a meal, place the cut spears in iced water for a few hours and wrap and store in the fridge until you have sufficient for your needs. On a large bed you can be cutting almost daily. If you allow them to grow taller they can start to open and lose their delicacy. In year three I would not harvest beyond three to four weeks. If the new spears start to become small and spindly you have probably over-harvested them. You have to leave some good spears to become good foliage to feed the roots for the following year. As for varieties, a popular one is Connover’s Colossal but I find this too large and only suitable for soups. Try Ariane or Mondeo both of which are male varieties that ensure the bed remain true to type. Globe artichokes yuk.
Mike I’Anson – March 2016