As you may know, quite a few of the plants we love and have growing in our gardens aren’t propagated vegetatively, through seeds or offsets, but start life in a lab. This includes not only many of my beloved agaves and mangaves, but also most commercially grown perennials and even the orchids you find in grocery stores and garden centers.
Earlier this week, I had the opportunity to go on a field trip with my volunteer group from the UC Davis Arboretum Teaching Nursery to visit a plant tissue culture lab in the Sacramento area. I already had a high-level understanding of what tissue culture (or micropropagation) is and how it’s done, but I had never seen a lab in operation, so I was stoked to go.
I read somewhere that a tissue culture lab is essentially a plant factory combined with a surgical operating room. That’s a good comparison. Instead of growing plants in soil from seeds or traditional cuttings, technicians culture plants in sterile, nutrient-rich gels inside glass or plastic containers. This allows the lab to produce many thousands of genetically identical, pathogen-free plants in a relatively small footprint.
The company we visited is Micro Paradox, a tissue culture lab that propagates a wide variety of plants — from succulents (including agaves) and California natives to shade trees and house plants all the way to commercial nut and fruit tree rootstocks. Founded in 2010 by plant pathologist Dr. Parm Randhawa, the company was named after the Paradox hybrid walnut rootstock, a cross between the black walnut (Juglans hindsii) native to California and the English walnut (Juglans regia). The black walnut is perfectly adapted to northern California’s mediterranean climate but produces inferior fruit. The English walnut produces superior fruit, but it struggles in California. Paradox combines the best of both — vigorous growth and high-quality nuts — but it had historically been difficult to propagate uniformly from cuttings. Micro Paradox found a way to produce uniform clones through tissue culture, a real breakthrough.
Nut and fruit tree rootstocks — primarily walnuts and almonds, but also cherries, peaches, and nectarines — are still Micro Paradox’s bread and butter, but in the last 10 years, the company has branched out into ornamentals and now produces hundreds of different varieties of everything from agaves, hesperaloes, and yuccas to tropical plants like bananas, philodendrons, alocasias, and ficus. In fact, agaves have become a focus; Micro Paradox now produces a couple dozen species and cultivars, including some variegated sports that were discovered in-house and are only available from Micro Paradox.
So much for the background. Let’s take a closer look at how things work at Micro Paradox. Vice president Simran Randhawa gave us an in-depth tour of the various areas. I took photos and will attempt to describe the various stages in easy-to-understand language.
The first stage is to prepare the tissue culture media — essentially containers partially filled with a gel-like substance (typically water and agar gum as well as macro- and micronutrients and precise ratios of growth hormones). Absolutely sterile conditions are mandatory in the media room because even a single fungal spore or other contaminant can ruin a batch.
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| The word “agave” gets my attention anytime |
In the transfer area, technicians work under
laminar flow hoods that continuously blow ultra-clean filtered air toward the work surface, pushing away any airborne molds and bacteria that would otherwise cause contamination.
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| The blue rectangles are the tops of the laminar flow hoods |
In the transfer area, three main procedures take place:
1. Small pieces of tissue (“explant”) from the donor plant are sterilized and placed on fresh gel media enriched with cytokinins, plant hormones that promote cell division. The explants are then moved to the grow room (see below) where they develop side shoots.
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| Sterile workstations |
2. A single plant produces multiple side shoots, which are continuously subcultured (divided and transferred to fresh media) every few weeks.
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| Technician dividing plantlets |
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| Sterile conditions are critical |
As you can see below, these pieces are surprisingly tiny. It’s pretty miraculous that they will ultimately result in real plants.
The photos below were taken in the grow room. I loved the racks illuminated by grow lights:
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| The lighting in the grow room is almost cinematic |
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| Glass vials with plantlets |
3. In the transfer area, individual plantlets are transferred to a medium containing auxins, hormones that induce root formation. The sterile containers then go back to the grow room. Within weeks, the root system begins to form.
When they’ve reached their target size, the plantlets are moved from the grow room to a non-sterile area outside the lab. There they are taken out of the growing medium and potted into a porous soil mix.
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| Agave trays waiting for agave babies |
Because the plantlets have spent their lives so far in ~100% humidity inside sterile containers, they now move through a series of greenhouses with decreasing humidity levels to get used to the outdoor environment.
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| Greenhouses, our group on the right |
I love seeing endless expanses of small plants, and the Micro Paradox greenhouses didn’t disappoint.
Micro Paradox has been tissue culturing Agave ‘Blue Glow’ in large quantities, and over the years they have discovered several variegated sports that developed spontaneously in the lab. A few of them, ‘Frost Glow’ and ‘California Glow’, have been put into production:
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| Agave ‘California Glow’ |
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| Agave ‘Frost Glow’ |
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| Agave ‘Blue Glow’ with half-moon variegation |
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| Agave ‘Blue Glow’ with various forms of variegation, including medio-picta, streaking, half-moon, and marginated |
This unnamed ‘Blue Glow’ sport with very pronounced medio-picta variegation (creamy stripe in the center) is particularly striking:
As I mentioned earlier, Micro Paradox also produces a number of edible tropicals like bananas as well as house plants, including alocasias and colocasias, monsteras and philodendrons, and ficus.
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| Red ornamental pineapple (Ananas ‘Mila’) |
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| Red ornamental pineapple (Ananas ‘Mila’) |
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| Blood banana (Musa acuminata ‘Zebrina’) |
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| Philodendron erubescens ‘White Wizard’ |
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| Alocasia ‘Pink Dragon’ |
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| Alocasia ‘Pink Dragon’ |
After leaving the humidity- and temperature-controlled greenhouses, many of the plants (especially the succulents) end up outside. Some are set aside for direct-to-consumer sales on Micro Paradox’s
retail website, MicroStarts.com:
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Others are being grown on to larger sizes for eventual sales to local retail nurseries:
Several things stood out during our visit: The facility is much larger than I had expected. As many as 800,000 individual plants are in propagation. That’s a number I have a hard time wrapping my head around.
Judging by what VP Simran Randhawa said, the company is not content simply relying on what has worked in the past. While nut and fruit tree rootstocks will always be a major part of their operations, they’re constantly looking for promising new material to add to their inventory. I found this sense of curiosity to be very refreshing. Of course, I hope that this will include many more agaves and other succulents.
The bulk of Micro Paradox’s sales is wholesale to other growers and retail nurseries, but a selection of their plants are available to consumers through their
Etsy store and their
MicroStarts retail website.
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| One of my ‘Pixie’ agaves, now 3" across. I expect it to get a little bigger, but not much. |
Last year, I ordered a 4-pack of
Agave ‘Pixie’, a dwarf mutation of ‘Blue Glow’, and was very happy with the quality. At the time, I had no idea who is behind MicroStarts — and that I would eventually get to visit their facility!
© Gerhard Bock, 2026. All rights reserved. To receive all new posts by email, please subscribe here.
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