We are very excited about growing Asparagus! While it can take up to 3 years before asparagus is ready to harvest, this perennial plant can keep producing for up to 20 years! Talk about commitment and abundance in return – we like that!
In our research, we have found some great advice that we would like to share with you. Feel free to share your tips and tricks with us in the comments section below.
Crowns vs Seeds
Plants can be grown from “crowns” or germinated from seed. Most opt for the crowns since seeds take an extra year to harvest. Crowns are ready to harvest in 2-3 years. Try not to plant anything over two years old as they tend not to transplant well.
Since we have asparagus seedlings, we will be focusing on growing seedlings in this post.
Choosing the Right Position for your Asparagus Bed
The most important thing to remember when deciding where to plant your asparagus is it’s longevity: it can keep producing for up to 20 years! They also grow quite tall so you want to position them where they won’t cut off sunlight from your other beds.
You also need to provide a spot that is protected from strong winds so as not to damage the stems. You may also want to make a support with wooden sticks or bamboo to ensure they don’t fall over.
Asparagus tends to bolt and go to seed if it gets too warm too quickly in the spring. Having said this, asparagus does require a good amount of sunlight, so find a spot that is both sunny and protected from harsh midday sun.
Ensuring Optimum Soil Conditions
Preparing the soil needs special attention as you won’t have any other chance for this. The soil must be conditioned and cultivated deeply with lots of compost. This is a heavy feeder and thrives well in soil fertilized with organic matter. They prefer rich sandy soil for the asparagus spears to easily shoot through.
Poor levels of nutrition in the soil can cause fibrous spears and weak growth so take care in determining your soil PH and nutrient levels when preparing your asparagus bed.
Ideal pH levels in the soil for asparagus are 6.5 to 7.5. Asparagus will not grow in soils with a pH of less than 6.0.
Asparagus loves NITROGEN. Here are a few tips for ensuring good levels of nitrogen for your plants:
- Grow Comfrey on the edges of your bed. Pick the leaves and allow them to wilt for a day or so. Use the leaves as mulch for an added nitrogen boost.
- Add well rotted, composted manure to your beds.
Asparagus needs PHOSPHORUS to stimulate good root growth. This is essential for healthy asparagus! Good sources of phosphorus are bone meal and well rotted compost.
Asparagus also likes a good supply of POTASSIUM. Compost (with banana peels if you have them) and wood ash (particularly hardwood) are great sources of potassium.
Keep your asparagus bed free from weeds as they will compete for space and nutrients.
Preparing the Asparagus Bed
You can prepare your asparagus bed way ahead of transplanting time. Grow cover crops to loosen, condition, and add organic matter to the soil. When the asparagus is ready for transplant, you can prepare the soil bed by doing the following:
- Clear the plant bed up from weeds, soil clumps, and rocks.
- Dig a trench about 25cm deep and leave the soil from the trench along the ridges.
- Spread about 5cm of well-rotten manure at the bottom of the trench and pat it down while ensuring you aren’t compacting it too much.
- Then add about 10cm of rich, loose soil on top of the trench.
Transplanting Asparagus Seedlings
Seedlings are ready for transplant after 10 to 12 weeks after or around the last frost date. The earlier the seedlings are transplanted in spring, the better.
Place the seedlings around 50cm apart in the ridge.
Fill the trench back with the soil alongside the ridges up to the base of the plant. Keep some soil alongside the ridge to keep adding soil as the asparagus grows.
Keep the asparagus plants well-watered if you want longer shoots.
Caring for your Asparagus
Asparagus is rather thirsty but it does NOT like having wet roots as they tend to rot when they sit in soggy soil. Well drained and well aerated soil is key. A raised mound will greatly assist with this, along with adding earthworms to your bed to aerate the soil.
It is essential for the roots of the asparagus to stay cool during summer so it is advisable to grow tomatoes alongside your asparagus to help with this – and tomatoes deter asparagus beetle – or look at growing a green mulch such as clover that will not only help to keep the roots cool but will also also fix nitrogen into the soil and help with aeration.
For info about companion planting for pest control, click here.
Protect asparagus from strong winds by staking them up if need be.
Asparagus is a hardy plant and will survive most winters. You can mulch your asparagus beds with straw in Autumn to keep the roots protected throughout winter, especially if you experience frost.
Harvesting Asparagus Spears
Once asparagus plants are strong enough to be harvested, cut all new shoots in spring when they are about 15cm tall, snapping them off at the soil line. Many seasoned gardeners use a knife to cut below the soil line, but it is important to avoid cutting into emerging spears nearby.
The asparagus can be harvested for a period of about two to three weeks once the spears start to show. Keep a close eye on your asparagus so that you don’t miss the harvest! After harvest, allow the ferns to grow; this replenishes the nutrients for next year’s spear production. Harvest for 2 or 3 weeks.
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