Growing Asparagus in the Hot Zones

It’s the middle of June and we’re still getting a 
few new asparagus spears.  Photos by Mary Woody.

We’ve often heard the question, “Can I grow asparagus in Florida?”  As usual, the answer is “Depends,” or “Maybe.”  Depends on the variety and where you plant it, and maybe if the weather cooperates and conditions are just right.   

At the VegHeadz garden at least nine years ago we planted asparagus in the garden.  It was not very successful—full sun, irrigated.   But asparagus makes seeds, and we were gifted with a volunteer plant further down in the garden where it received some shade part of the day.   It survived and multiplied.   We rarely harvested any, except to graze a stalk or two if any happened to be fresh on our weekly work day.   This gave the bed the opportunity to get well-established. 

We eventually moved the roots up into the sunnier herb beds where it also survived because the plant was now adapted to our particular location   When asparagus leafs out it takes quite a bit of space so it was eventually dug up and shared with gardeners who wanted to plant it at home.   One clump was planted in the edible forest, a somewhat shadier area, where it has persisted and multiplied. That is the bed pictured here.  It is not irrigated nor fertilized, and it receives quite a bit of shade, particularly in winter.  It is also in a lower part of the garden, which is always a few degrees colder in winter.  Asparagus needs to become fully dormant in winter.   

Simulating Dormancy: In regions with mild winters (like Florida), asparagus will not naturally go dormant. To force a rest period and induce new spring spears, cut all the yellowing or dead foliage back to the ground in mid-winter (e.g., January).

Variety:  The identity of the variety we are growing has been lost to time, but the top varieties for warm zones include:  

         UC-157: A University of California hybrid specifically bred to excel in warm, subtropical climates

        UC-72: Highly productive and resilient to high heat

        Jersey Knight: A vigorous, all-male hybrid that produces large, thick spears and resists crown rot

        Purple Passion: Produces sweet, tender purple spears and performs well in hot southern regions.  

Planting the Bed:  Plant 1-year-old dormant crowns in late winter to early spring.  Dig a trench about 6 to 8 inches deep.  Place the crowns 12 inches apart and cover with just 2 inches of soil. As the shoots emerge throughout the summer, gradually fill the trench to the top so the roots are sufficiently deep. 

Soil & Sunlight: Plant in a site with 6 to 8 hours of direct sunlight, but anfternoon shade is beneficial.  Best is sandy, well-draining soil rich in organic matter. Asparagus prefers a soil pH of roughly 6.5 to 7.0. 

The Waiting Game: Do not harvest any spears during the first 1 to 2 years so the plant can establish a strong root system. Allow the spears to grow into tall, feathery ferns. Once established, limit harvests to 4 to 8 weeks in the spring, leaving some spears to mature and feed the roots.  

Maintenance: Keep the bed heavily mulched to retain moisture and suppress weeds.  Nitrogen fertilizer can be applied during the growing season to promote robust fern growth.

The final word, you will be able to harvest asparagus and it will be delicious, but it is unlikely to be the fat succulent spears seen in the grocery store in spring.  

To the right of the asparagus is Malabar 
Spinach growing on a small trellis.  
Behind it is our recently expanded blueberry
patch.

We use bamboo from our garden to build simple 
barriers to keep blooming asparagus out of
pathways.  

Open House and Plant Sale 2026

The day began overcast with threatening rain, but we beat the odds. Eager plant buyers formed a long line before the gates opened at 9 o’clock, where we offered for sale over 3500 plants propagated by Master Gardeners from the seven Extension demonstration horticultural beds, as well as Master Gardners’ own yards. The plants were beautiful and buying was brisk.

Many people enjoyed touring the demonstration beds, the orchard and the VegHeadz vegetable garden, food Forest, grape arbor and rain garden.  Hundreds of visitors wandered among the beds, got ideas, asked questions and enjoyed the day.  Kids got to dig potatoes and sample green beans and Roselle tea. Hundreds of packages of free seeds were to taken home to plant in gardens.  We love having people in the garden and we hope they’ll take home some ideas for their own spaces.

The VegHeadz Garden is Blooming and Bearing

 

Most of the people who have been growing the flowers and vegetables that are thriving
in the garden.

The VegHeadz have been working hard to make our garden look it’s best for the open house and plant sale this weekend. Rain is predicted and as much as we need it, we hope it will hold off until after our yearly event is over. Here’s a preview of what you will see if you visit the VegHeadz garden.

Just one view

Peppers

Blackberries

Sunflowers

Yarrow

Nasturtiums

Cosmos

Pole beans

Black Tomatoes

 

Green Tomatoes

Red Tomatoes

Eggplant

Peas

Squash

Biochar Trial Beds Fall 2025 — The Results are Finally In!

The crops have been harvested from the four trial beds in the VegHeadz Garden   Get our report on the results here. 

The biochar trial furnished much new information. The most important thing we learned was that there was no indication that the biochar did any harm to the garden.   Please understand this was just an informal test in our garden. A truly scientific trial would include multiple plots with each different amendment.  It would be controlled under  strict guidelines.  Our test consisted of measuring inputs,  observing regularly, and measuring outputs, but it would not qualify as a scientific test.  Still it was worthwhile and we learned quite a bit. 

The plants tested were collards and daikon radishes. The radishes did not do well, possibly for two reasons. The most obvious reason was freezing.  They were much more drastically affected by the winter freezes than the collards. The other reason is most likely the high pH of the soil. The final soil test reflected pH of 7.5 in all beds and daikon radishes prefer a more acidic environment. Perhaps we’ll grow some daikons and add sulfur to the soil to see if the results differ.  Close observation, testing and comparing in a more or less controlled environment, and recording and comparing results, are the best ways to figure out what’s going on in your garden.

The most important thing we learned was that all our fears about the biochar increasing the pH in the garden beds were unfounded. The pH did increase, but it also increased in the control bed, which had no biochar added. Compost tends to have an alkaline pH in any event, and we feel that the increase in pH was caused by the compost. Again, application of sulfur, peat moss, or other acidifying amendments would most likely be beneficial.  

There was a moderate but positive increase in plant survival, production, and plant health in the bed that was amended with compost, first co-composted with biochar for a period of 6 to 8 weeks with no pH adjustment. This was our most successful bed.  Again, repeating the test with each amendment applied to multiple plots would produce a more reliable result and eliminate the possibility of coincidence and other unknown factors.

For those wishing to use biochar in their gardens, we make the following recommendations, based on online research sources and our experience so far:

• Determine the source of the material used to make the biochar you intend to use and the process by which it was created.   Research sources indicate that the best biochar source material for application in vegetable gardens appears to be lignin-rich biomass from hardwood like oak and softwood such as pine. The best processing temperatures for creating biochar from these materials for use in gardens appears to be 400-700°F. 

• Start with a small ratio of biochar to compost, 5% to 10%, and compost them together for a period of at least six weeks to charge before applying to the soil.  This allows time for micronutrients to infiltrate the pores of the biochar and for microorganisms to multiply and populate the biochar. The mixture should be kept moist, but not overly wet as microorganisms need access to oxygen to multiply.

• Keep track of how much biochar you are adding, particularly if adding in more than one application.  5% to 10% of the soil volume is the recommended application rate according to most sources.  It is not recommended to ever add more than 20% biochar to the soil.  Biochar decomposes extremely slowly, and it cannot be removed once it is added to the soil.

• See the entire report on our Fall 2025 biochar trial here and the biochar handout under “soil amendments” in the Gardening Resources section of the left sidebar on this blog.  The handout includes how to calculate how much biochar to add to achieve the desired ratio in the soil and information about pre-treating the biochar, plus a list of many of the biochar research resources we referred to.

A new trial is under way for spring 2026.  The spring trial involves comparing results when adding our organic fertilizer mix and biochar in various combinations to the trial beds.  Test plants will be peppers and green beans.  

We are also trialing the addition of organic fertilizer to half of the tomatoes in the B rotation beds.  The same number and variety of tomato plants have been planted on each side of the bed.  It will be interesting to learn whether this makes a difference, not only in growth and production, but in pest and disease resistance, heat tolerance, and length of bearing season.  So far the unfertilized plants look bigger, but they have not yet set any tomatoes.  The fertilized plants have many small tomatoes.  We’ve also added the fertilizer to the potatoes in the C rotation beds.  So far they look amazing.  We’ll see how many potatoes they produce and whether they are free of blemishes.

Wednesday in the Garden

 

A few weeks ago (previous post) we pictured Peggy pruning the Katrina
roses.  This is the result.  It took her six hours to complete the 
job, but it was sooo worth it.  

The weather for Wednesday work days the last several weeks has been perfect--cool, sunny, breezy.  It's wonderful to just be outside with friends doing something productive.  Walk with us through the garden where the plants are enjoying the weather too and we are getting ready for the Spring Open House and Plant Sale on May 9.  Don't miss it!  We hope to see you there.  Let us know you saw it on the VegHeadz Blog.  

A beautiful day in the garden.

Potatoes

A great mix--Rosemary,
onions, garlic, squash,
tomatoes

Bush beans

Zinnias.  The pollinators
love them, and so do we.

Peppers, onions, 
squash, tomatoes

Lots of work has been going
on in the Forest Garden

And it's looking good

Come to the Open House and see
what we do with our Bamboo

Pruning

Pruned grape vines. Muscadine Grapes 

bear on new growth, so each spring the 

previous year’s lateral vines extending 

from the main vines or cordons, need to be 

pruned back, leaving anywhere from 

2 to 6 buds or nodes. 

Early spring is a good time to prune most trees, shrubs and vines. Learn more about how and when to prune fruit trees by referring to the fruit care calendar under Gardening Resources in the left sidebar, or entering “prune” in the search box on the right.

We’ve been doing some major pruning in the VegHeadz garden and in the food forest. Our food forest is small and we need to prune quite heavily every three or four years to keep our trees at a reasonable size.  Pruning is also important to ensure that the ripe fruits will be within reach for hand picking.

Peter does a short training
session before
pruning begins

Almost done

Don’t waste the vines.
Wreaths and other projects
are easy to do while the
vines are still fresh and flexible.  
Mary and James made these in
about 15 minutes.

“

And then there’s the rose arbor. 
Each spring Peggy prunes the vines of the
Katrina Roses (Peggy Martin Rose—no relation).
In about six weeks, they will bloom profusely.

In the food forest, the Dwarf Black Mulberry
had become twiggy and overgrown.  
Peggy directs, George prunes, and
James hauls the cutting away.  

Pruning done.   Within two weeks (in mid March), all pruned trees were 
putting on new growth.  From left, a leafy Mayhaw which needed
little pruning, next to it a Peach, then forward is Wax Myrtle.   Large shrub in the back, 
is Elderberry, in front next to the entrance arbor is the Mulberry,
seen through the arbor is a fig, and to the right of the sunburst trellis
is an American Beautyberry, all pruned and ready for spring renewal.  

Photos by Emily Kelly

Wednesday in the Garden

Our youngest gardener.
He really enjoyed the 
tender new asparagus spears. 

It’s Spring!  Planting and seeding are still under way.  All the weeding and prepping we have been doing are paying off.  One of the most rewarding parts of gardening is watching as seeds sprout, new leaves and blooms appear, and fruit begins to develop.  

Spend some time with us in the garden.     

There’s more than one way to
carry an unwieldy load.  

Cardboard and mulch,
cardboard and mulch

Harvesting the last of
winter’s greens

Building a new blackberry
patch, a great addition to
the food forest

The mulchers have 
depleted our supply,  
Time to order more.
  

Weeding in the perennial 
pollinator beds before
they spring back to life.

Potatoes are planted here

It didn’t take them 
long to start 
growing.

 

A nice bunch of carrots

The garden is a great
place to spend time
with friends

Cathi and Evelyn

Photos by Emily Kelly, Lisa Jacobsen, and Janis Piotrowski