Grow & cook



As­para­gus is un­like any other veg­etable you’ve ever grown, and yet so un­de­mand­ing that it should be in all kitchen gar­dens with cooler cli­mates in South Africa. This highly nu­tri­tious peren­nial will keep on pro­duc­ing for years, but off the shelf the spears usu­ally come with a hefty price tag and an even heftier carbon foot­print.

Al­though it be­longs to the lily fam­ily, as­para­gus grows as a fern. The fern is a mod­i­fied stem that pho­to­syn­the­sises to pro­vide en­ergy for the rhi­zoma­tous root ball or crown. The spear we har­vest and eat at its most ten­der and tasty is the im­ma­ture part that is formed by the crown. If left un­har­vested, a spear un­folds into the woody ined­i­ble fern of up to 1,8m high.

Bat­tle of the sexes?

As­para­gus is a dioe­cious plant, which means that it has sep­a­rate male and fe­male plants. The males pro­duce more and thicker spears than fe­males and are there­fore prefer­able. It’s easy to dis­tin­guish be­tween male and fe­male plants: males pro­duce a small pale yel­low flower and fe­males a bright red berry about 8mm in di­am­e­ter.

The ber­ries, when fer­tilised, con­tain two or three black seeds each. The ripe ber­ries can be har­vested and the seed col­lected for sow­ing again; if left unchecked they will read­ily self-sow. This is an­other rea­son why it’s bet­ter to plant male plants as they aren’t as likely to cause over­crowd­ing in the as­para­gus patch.

How to plant

Es­tab­lish­ing as­para­gus re­quires lit­tle more than pa­tience…

SOW­ING If you grow them from seed you need to wait two years for the crowns to ma­ture be­fore you can start to har­vest the spears. In the third year you can start to har­vest for about a month of the grow­ing sea­son be­fore al­low­ing ferns to ma­ture and strengthen the crown. From the fourth year a proper har­vest of two to three months can be made. The good news is that a plant will keep on pro­duc­ing its highly nu­tri­tious bounty for many years.

The best time to sow is at the very start of spring. It is ad­vis­able to sow as­para­gus in 15cm pots and only trans­plant it at the start of the third spring. For the av­er­age fam­ily >

20 to 25 plants should be enough – but be­cause you’ll se­lect only the males for trans­plant­ing, you’ll need to sow at least 30 pots. Use a mix­ture of pot­ting soil and ver­mi­culite. The seeds can take up to 10 weeks to ger­mi­nate. Again, pa­tience is key.

By the sec­ond au­tumn you’ll be able to dis­tin­guish be­tween male and fe­male plants and se­lect the more pro­duc­tive males. Sow­ing in pots first and trans­plant­ing later also al­lows you to plant the crowns deeper than it would have been pos­si­ble to sow the seed.

It is im­por­tant to plant as­para­gus in a spot that re­ceives full sun as most of the prob­lems that a plant can ex­pe­ri­ence stem from con­di­tions that are ex­ces­sively damp. Re­mem­ber that the area you se­lect will be its home for at least a decade!

Plant­ing depth is very im­por­tant.

If the crowns are too shal­low, you’ll get a large num­ber of thin spears; plant it too deep and you’ll only have a cou­ple of very large spears.

SOIL Hav­ing se­lected the lo­ca­tion, pre­pare the soil for plant­ing by dig­ging a trench of 20cm to 30cm deep. Mix the ma­te­rial from the trench with an equal amount of rich com­post. If you know the soil is acidic, some lime can be added. Us­ing the mix­ture, fill the trench half­way be­fore plac­ing the two-year-old crowns about 40cm apart. Cover the crowns with 5cm of soil at first, then fill the trench with the re­main­der of the com­post-and­soil mix­ture as the plants grow.

As­para­gus can tol­er­ate brack­ish or al­ka­line soil and will even grow in coastal areas, but prefers sandy soil. It will be nec­es­sary to im­prove the drainage where soil is more dense. This can be achieved by rais­ing the bed through dig­ging the trench a lot shal­lower – only 10cm – be­fore plant­ing as de­scribed above. A layer of com­post and mulch should be added at the start of spring ev­ery year.

MULCH A layer of straw or sim­i­lar mulching ma­te­rial about 10cm deep should be ap­plied to as­sist with mois­ture re­ten­tion and tem­per­a­ture reg­u­la­tion – but, more im­por­tantly for as­para­gus, it will also help com­bat weeds. Bear in mind that this will have an im­pact on how much wa­ter reaches the roots. It is there­fore rec­om­mended that drip ir­ri­ga­tion is in­stalled be­fore mulch is ap­plied over the sur­face. Al­ter­na­tively you can wa­ter by hand once a week us­ing a hose or wa­ter­ing can with the noz­zle re­moved.

As­para­gus re­quires reg­u­lar wa­ter­ing through­out sum­mer. It is best to wa­ter less of­ten but more thor­oughly to en­cour­age root growth. One or two deep wa­ter­ings per week should suf­fice.

Va­ri­eties and com­pan­ions

It is rel­a­tively easy to come by the green and pur­ple va­ri­eties in South Africa now. The white spears are sim­ply green ones that have been blanched. This is achieved by rais­ing the bed above the crowns us­ing a very light soil mix such as com­post and sand, or straw mulch. The spears re­main white for as long as they are kept away from sun­light.

Com­frey makes a good com­pan­ion to as­para­gus and can be planted along the edge of the bed, in­ter­spaced with the crowns. Com­frey leaves can be cut and laid down as mulch on a reg­u­lar ba­sis – as it breaks down it acts as a good source of potas­sium.


Har­vest­ing from the third year en­tails care­fully re­mov­ing the ma­te­rial around the young spears and cut­ting them at the base with a sharp knife early in the morn­ing. Be sure to har­vest only about 75% of the young spears, leav­ing the other 25% to ma­ture and sup­ply en­ergy to the crown for the next sea­son’s har­vest.

By the first frost the ferns will have died and browned. They can now be cut at ground level.

Pests and prob­lems

Very few pests and dis­eases af­fect as­para­gus in South Africa. Take care not to over­wa­ter plants as this could cause root rot and other fun­gal dis­ease. Aphids are of­ten a tem­po­rary an­noy­ance but can eas­ily be sprayed off with wa­ter or washed off af­ter har­vest­ing. Pretty as­para­gus bee­tles may feed on the tips of spears or lay their eggs there. These bugs don’t like the smell of toma­toes, so if it isn’t pos­si­ble to plant some toma­toes close by, sim­ply pick some to­mato leaves, and crush and scat­ter them in the as­para­gus patch to de­ter the bee­tles.

ABOVE, FROM LEFT A male as­para­gus plant in flower; fe­male plants can be iden­ti­fied by their red ber­ries. OP­PO­SITE The green spear that ends up on your plate is in fact a mod­i­fied stem that supplies en­ergy to the root ball or crown be­low the soil sur­face.

Sow­ing as­para­gus in pots to trans­plant them later al­lows for se­lec­tion of the more pro­duc­tive male plants, and you’ll be able to plant their crowns deeper than you’d be able to sow the seed.

Al­low ap­prox­i­mately a quar­ter of the spears to ma­ture so that they can pro­vide en­ergy to the crowns for the fol­low­ing sea­son.

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