If you have room for asparagus it is the finest delicacy in the garden. Also it is ready in the late spring along side purple sprouting broccoli, another delicacy. You could add a third in sea kale. Throw rhubarb into the mix and you have a proper end to the ‘hungry gap’ period before the early summer crops such as broad beans and peas come into their own.
Asparagus is a long-term prospect, an investment. When you plant the crowns, depending on their age, you must let them grow for at least one if not two seasons before any harvesting can take place.
It is a bore but once the bed is in you have it for many years. The ones in my garden have been in for 9 years and they are just getting warmed up. The spears are getting stronger and stronger each year with just some compost to feed the bed and perhaps a layer of seaweed from the beach when a winter gale blows some in (make sure you do this before the end of January otherwise it won’t rot down in time and the spears will have to force their way through it which they don’t like).
There are no pest or disease problems to worry about and very little to do. The only three things that must be done are:
- Keep the bed weeded and especially free of perennial weeds.
- Cut the fern down to the ground in early winter.
- Feed the bed after you have cut it down.
Getting a bed ready.
Asparagus needs to be grown in quantity to make it worthwhile. I suggest a minimum of eight to ten plants to give a decent crop each year. Those plants, or crowns as they are known, must be spaced at the very minimum 30cm apart with the same between rows. 45cm between rows is preferable in my opinion. They like space.
If the day ever dawns when you have to move or dig up a mature asparagus bed that has been planted at 30 or 45 cm spacings, what you will find down there is a gigantic octopus made up of thousand upon thousands of tentacles all of which are holding on to the soil and each other. Imagine an old-fashioned kitchen mophead and multiply it by ten. That is what a mature asparagus crown looks like. Extraordinary. Space, therefore, is good. Make it 45cm if you can.
And asparagus should be planted as a bed, not as single plants dotted around the garden. They like to grow together and be apart from other plants. This is how they grow in the wild, on the seashore above the high tide mark where they can get their roots deep in the sand.
You need to plant asparagus crowns at a depth of 20cm so there is quite a bit of digging involved for a double bed of 2.5m long and 1m wide. Dig the soil out and throw it up either side and at the ends until the trench is empty and plant at the suggested spacings. Throw the soil back.
Sowing asparagus seed will mean a four-year wait until first cropping, so that is out. You could by little plants from a garden centre/nursery but if they are in 9cm pots they will only be one year old, therefore you still have a three-year wait. Buy two year old crowns and you only have two years to wait. Three-year-old crowns, if you can get them, reduce the wait to one year. But once they are in you have them for life. They will begin to weaken a bit in terms of size of spears after 20 years….but really it is a good return.
So if you plant an asparagus bed to the spacings suggested above then you are going to have a double row of 10 plants spaced 30cm apart in two rows that are 45cm apart. That means you have to dig a bed that is at least 100cm wide. The crowns are ordered in March and will arrive looking like mopheads or dried out octopus with many more tentacles.
You spread them out in the rows. It is the distance from the centre of each crown that should be 30cm. Don’t worry if the tentacles overlap a bit. Once the two rows are laid out you throw the soil back in the trench. It will sit proud over the bed like a freshly filled in grave. Mark it with a cane stuck in each corner. Then mark another 30cm out from the bed and make your path there.
Maintaining the crop.
Weeding is an important part of asparagus care. The spears come from crowns that will be with you for many years and they must be given all help possible. One of the most important steps to take is to ensure that no perennial weeds find their way into the crown. Docks, thistles, ground elder or dandelions. These are the classic weeds that can do this. Their way in will be where the spears break the surface so the roots have an easy journey down to meet the asparagus crown roots. Once there it is impossible to get rid of them.
Harvesting and the asparagus ‘season’
When you harvest asparagus on no account use any tool that calls itself an asparagus knife and is used to cut the spears below the soil surface. This is fatal and will almost certainly cut or damage other spears that are not yet visible. When you harvest cut the spear off at ground level with a sharp knife.
The harvesting season runs from the time that the first spears nose their way out of the ground until the third week of June. Then the cutting must stop and any further spears coming through must be left to grow tall, produce leaf (fern) and die naturally in the autumn. In this way they return energy to the crown and keep it healthy for years to come. Continual harvesting all through the summer and autumn would exhaust the crown and quickly render the crop worthless.
In November when the foliage turns yellow, then brown and dies cut it back to ground level and remove it to the compost heap. Be careful though because it is slightly spiny. Use gloves.
The bed is then empty. This is a good time to give a good weed and dig out any perennial weeds that have snuck in. Don’t dig too deep, only three to four centimetres and certainly no deeper around the crown.
Then cover the bed in home made compost and/or fresh seaweed to a depth of six to eight cm.
Pests and Diseases
There are very few problems to look out for with asparagus. Success with asparagus is all about doing the right thing at the correct time of year. Most important of all is to cease all harvesting in June. I cannot stress the importance of this enough.
Gijnlim is an early variety that produces thin spears which I prefer because the flavour is more intense. Guelph Millennium on the other hand is a bit later with chunkier spears.
Mercaptan, is the sulphurous compound which when broken down causes the urine to smell almost instantaneously after eating asparagus. It is harmless and there is nothing wrong with you. Rather asparagus is immensely healthy with high levels of fibre, vitamins and minerals. Like all vegetables it should be grown organically and eaten as quickly as possible after harvesting for maximum nutrient uptake.
And finally, because fresh asparagus is so rare, and the homegrown organic is a near priceless commodity, you will make many friends if you give away or even sell the surplus. This will help your asparagus beds because the moment a spear reaches 10-15cm in height it is ready to be cut. What’s more it should be cut because that way the bed will go on producing more.