January 10, 2023


My Mantra Word for 2023

I don’t create New Year’s resolutions, but I do usually create a mantra for myself or business each year to keep in mind when making decisions. Recently my good friend and business partner Maria Failla asked me what my word or mantra was for the new year. I’d been noodling on it, but hadn’t nailed down just the right word yet. Then, it hit me…

Totipotency. That’s it, my mantra word for 2023. It’s also one of my very favorite botanical (biological) vocabulary words.

Totipotency (in the context of botany): The ability of a single plant cell to grow, divide, and differentiate into an entire plant

Halleck Fungi Block Print

Halleck Fungi Block Print
My first attempt at wood block printing in 30 years, from a recent fungi illustration I completed. It's not perfect...but it was fun!
PC: Leslie F. Halleck

Most of us get put on a hamster wheel at a young age. We’re all expected and trained to choose one narrow path upon which to earn a living and ultimately define ourselves as adults. The reality is all of us have so much more creative potential and or varied proclivities than that one path allows to manifest. While that one main path can certainly form a strong trunk that anchors and ground us firmly, providing stability and direction, ultimately, we must branch out if we are to grow a large leafy canopy capable of nourishing our whole selves…from roots to shoots.

Just as a seed is totipotent, containing all the genetic information needed to grow and develop into all varied functioning parts of a mature plant, so are we…seed like…totipotent.

While I certainly have an innate passion for plants, nature, and gardening, and have carved out a successful professional path in the horticulture industry, horticulture, singularly, does not define me. As a person, I encompass many seeds of passion, the first being art, that when germinated add necessary flesh to my being.

Totipotency is what guided my decision to take a step back from all my hard-earned work in the horticulture industry, and start a well-earned sabbatical. A sabbatical that will allow me to also take a step back from myself, observe and see what is missing, and begin to germinate all the other seeds of passion from which manifest my whole self.

The last few tough years of the pandemic have “helped” to break down those hard seed coats. After all, you can’t manifest your totipotency before first breaking whatever dormancy has been holding you back. That’s the theme and plan for the next year, the year I spend being 50. My days are and will be filled with new learning, creativity, and manifesting in tangible form a massive backup of art that’s been building up, patiently dormant, for far too long. And of course, I’m sure I won’t be able to resist a few interesting planty projects or opportunities if they manifest as well along the long as they help me branch out.

I hope you’ve found your word, or mantra, for the new year that helps illuminate any and all new paths and branches you hope to add to your very big and very whole tree of life.

What's the Difference Between Thanksgiving Cactus, Christmas Cactus, and Easter Cactus?

January 11, 2022

Learn About the Different Types of Holiday Cactus

I was contacted a few months ago by a reporter looking for accurate information on holiday cactus. I wrote up detailed answers to all their questions...only to get ghosted! SO, their loss is your gain. I decided to put up my detailed response as a blog post for paywall required!

Christmas Cactus

Q: Could you provide some background information on what a Christmas Cactus is, and the different types?

A:Christmas cactus are an unusual type of cactus that grows as an epiphyte or lithophyte (grows on trees or rocks), in habitats that are a bit shady and humid. Not exactly the type of environment you think of when you think cactus! Plants sport bright showing flowers in an array of vivid colors.

There is quite a bit of confusion when it comes to Christmas cactus, and the related Thanksgiving cactus and Easter cactus (in the Northern hemisphere). The name Christmas cactus refers to species and hybrids of cacti that bloom around Christmas time and belong to the genus Schlumbergera, which includes nine distinct species. Plants are Native to the coastal mountains of south-eastern Brazil.

There are also hybrids between the species. When you buy Christmas cactus, you’re usually buying a hybrid cultivar we call Schlumbergera x buckleyi, a cross between S. russelliana × S. truncata.

Halleck Holiday Cactus

Halleck Holiday Cactus
Visual differences between different species of holiday cactus
PC: Illustration & copyright Leslie F. Halleck

Thanksgiving Cactus

Thanksgiving cactus (or the false Christmas cactus) is S. truncata or hybrids thereof, with plants that bloom a little earlier than Christmas cactus. You can distinguish this species and its cultivars by the more pointed “teeth” on the leaves, versus the more rounded symmetrical teeth on Christmas cactus leaves.

Easter Cactus

Easter cactus, which are related and look like Christmas cactus with a series of rounded teeth on the leaves, has been reclassified as Rhipsalidopsis gaertneri -and hybrids thereof - but you’ll find them under a number of other pseudonyms in the Schlumbergera and Hatiora genera. They, as their common name would indicate, bloom around Easter time.

Top Tips for Caring for your Holiday Cactus

Providing enough light indoors is always your number one priority for the success of any houseplant. While Christmas cactus can tolerate lower light levels, if you are very careful not to overwater, the whole point of growing them is to get them to flower.

Plants will need medium to high light to bloom their best, so choose a southern or eastern window exposure if you have it or add a small grow light to your area as we head not the darker days of winter.

Water plants so that the growing media stays moist to the touch (but not soggy) and does not dry out completely between waterings. Plants are resilient, so if you forget to water and plants shrivel a bit, you can usually revive them with a good soaking.

Plants are very happy in a bright sunroom and grouped with other plants, which helps raise humidity.

Propagate Your Holiday Cactus

Vegetatively propagating holiday cactus is simple, as you can take stem tip cuttings or propagate new plants with just one whole leaf (roots and bud shoots will develop from the base of the leaf, just like many other types of succulents).

  • Carefully remove a section of stem or entire leaf pad by either twisting it off or using sharp clips.
  • Allow your cutting to rest on a dry surface for 2-3 days before you place into a small pot with moist potting soil or plug trays.
  • Let the growing media approach dry between light waterings, and before you know it cuttings will begin developing roots and buds.
  • Tips: Don’t take cuttings when plants are budding or in flower, and only take cuttings from healthy disease and pest free plants.

Note: be sure your particular plant is not a patented cultivar (it will say on the plant label or have PPAF on the label), as it is not legal for you to propagate or distribute patented plants.

IF/THEN COLLECTION at the Dallas Zoo

September 30, 2021

MUST SEE: The IF/THEN Collection Display of Women Scientists

Sponsored by The Texas Women's Foundation


Little known fact, I volunteer weekly at the Dallas Zoo as a keeper aide in the Zoo North Birds Department. Yes, it's true, every Wednesday morning you're likely to find me cleaning and tending the flamingo habitat at the zoo. The enclosure, a huge sunken garden, is populated with a flock of about 80 or so flamingos, plus several species of ducks, southern screamers, cranes, and a goose. My volunteer time at the zoo is something I look forward to every week and I love being able to give back to their animal conservation efforts.

I also happen to be a member of the Texas Women's Foundation and an avid women's empowerment advocate. So when I was taking a walk around the zoo grounds after my volunteer shift last week, I was beyond thrilled to discover this brand new IF/THEN Collection exhibit at the zoo! It's expertly deployed along the underground tunnel that connects Zoo North with the Wilds of Africa section of the zoo.

The striking, 333-foot-long mural, complemented by kiosks, features 12 amazing women who are making a difference in the fields of science, technology, engineering, and mathematics (STEM) whose work promotes conservation, advances research, educates the public, and inspires those around them. This temporary installation is generously funded by a grant from the Lyda Hill Philanthropies’ IF/THEN® Fund at Texas Women’s Foundation.

Be sure to walk yourself, and your kids, through this inspiring and informative display when you are at the zoo. You can find more details HERE. And be sure to show your daughter's what a scientist looks like!

Can I Grow Carrots Indoors with Grow Lights?

September 26, 2021

Indoor Gardening: Growing Carrots Indoors

It's al little trickier than you might think...

So, I received a question over on my youtube channel about growing carrots indoors...specifically, would 4 HO T5 retrofit LED bars in an 8-lamp Fluorescent fixture be enough to grow carrots indoors? I thought I'd share my answer with you here, as managing environmental conditions for many root crops can get a little tricky indoors:


It depends! My UCLA Extension Horticulture students LOVE getting this answer from me, but hear me out. It depends on the environment in which your growing - is there any other natural light, or does all the light come from the 4 (42-wattish LED bars?), the PPF output of each of the LEDs, and how long you leave them on. If you had a PAR meter, you could measure the PPFD of the 4 LEDs in combination, and adjust the height and duration for the desired crop...but you may find you can't produce an adequate DLI for fruiting/rooting crops, which really need the equivalent of full sun conditions.

DLI for Carrots

Let's assume a VERY general assumption that each of your new 42-watt Leds in the 5000-6400 K can each generate a PPFD of around 25 umol/m2/s at 12" above the plants (this is fiction, as I can't measure you lamps). So, 4 of them gets you a potential PPFD of 100 umol/m2/s. If you ran them for 1 hours that gets you a DLI (daily light integral) of around 4.3 Mol/m2/'s is only sufficient for low to very low light plants (definitely not fruiting/rooting crops). Carrots need a DLI in the range of 20-30 Mol/m2/day.

Now, if you put the lights closer to the plants it would increase your PPFD and thus your DLI...but you probably don't want to get any closer than that for maturing plants because it may burn the foliage or make conditions too hot for carrots – germination and root formation is best at cooler temps between 55-75F (13-24C) (of course in seedling/germination stage those lights need to be 3-4" from the seeds/seedlings, then raised as they grow). So you’re probably going to need to make sure the lamps are at least 18” above the plants, which will significantly reduce the PPFD.

Now, the PPF and thus potential PPFD of each of your LEDs might be more, but I can't know that unless I know more about the lamps and I can measure the PPFD with a PAR meter. So, I just got up on a chair and measured the light from TWO 6400k LEDs in a fixture in my office (I don’t know the age of these lamps but I’d suspect they are a couple of years old). The PPFD at 12" below the lamps (with additional light in my space) was 55.5 umol/m2/ the fictional example I just used above is probably pretty close to being accurate (4 of them would give me a little over 100 umol/m2/s at 12” and a low . So, if you use 8 lamps instead, you can ballpark doubling that PPFD, and get a DLI when run for 12 hours of around 10 Mol/m2/day which is sufficient for a lot of plants…but probably not beefy carrots!

Carrots are Long-day Plants

You can also increase the DLI by leaving the lamps on can grow many crops under grow lights running them anywhere from 14-24 hours. BUT here is the tricky part - carrots are long-day plants (photoperiodic) and they are triggered to bolt and flower by longer days/shorter nights (light period longer than 12 hours). SO, if you ran the lamps longer than around 12 hours a day to get a higher DLI you’ll trigger flowering, which stops taproot formation and makes it woody and unpalpable. Therefore, for indoor carrots (and other long day root crops), you really need to increase your light intensity as much as you can during a shorter, 12-hour photoperiod. So, MORE light intensity = MORE lamps during a shorter time period. With new, HO T5 quality LEDs, (such as Agro LEDs) You should potentially be able to hit a 20 Mol/m2/day DLI with 6-8 of the lamps run for 12 hours per day.

You can learn more about all of these metrics in my book Gardening Under Lights.

Tiny Plants: Codonanthe devosiana

September 23, 2021

A cute little African violet relative that likes to live on the dry side.

Looking for a miniature yet mighty houseplant that's easy to grow and flowers?

My cute little Codonanthe devosiana is blooming away under lights in my dining room...

Codonanthe devosiana is one of my favorite tough and tiny houseplants that gifts me with blooms indoors year-round. This succulent-like trailing gesneriad, related to African violets, sports dark, soft, pubescent leaves accented with the cutest white to pinkish trumpet-shaped flowers. OH, and in the wild species of Codonanthe have beneficial relationships with tree ants! Very cool.

These trailers are cute in small pots or hanging baskets. Mine has resided happily in this 2.5” porous terra cotta pot for a good while.

Just like African violets, Codonanthe spp. will do best and bloom with supplemental light indoors, unless you have more intense natural light. They can dry between waterings, but in small pots that will happen frequently, so you’ll probably water this plant more often than you would other succulent-like plants.

Happy #NationalIndoorPlantWeek

Indoor Plants: Burgundy Oxalis

September 22, 2021

Brighten Up Your Indoor Plant Collection

Oxalis offers up a breath of fresh burgundy foliage

Need some BURGUNDY foliage to shake up your urban jungle?

My Oxalis spiralis subsp. vulcanicola (commonly called volcanic sorrel) is one of my very favorite houseplants that sports deeply colored foliage. It always looks stunning when I move it to my white marble kitchen table for a temporary rotation (light is too low in this spot to leave it here indefinitely). This particular selection is also marketed under the trade name Oxalis Zinfandel TM.

This beautiful sorrel is tender perennial (in Zones 9-11) and an annual in cooler zones. Plants stay compact in a cascading form (10-12” wide-ish and about 6-10” tall-ish). Outdoors they are a part sun/part shade plant (wouldn’t take afternoon sun here in Texas very well, but morning sun is ok). So indoors an Eastern exposure would be ideal. Mine, which is currently in a 3-inch diameter container, sits in a North-facing window with supplemental light from a 40-ish watt LED grow light, which keeps it blooming regularly.

Plants do like to be consistently moist and will droop and drop leaves on you pretty quickly if you let plants dry out. So this plant is a good candidate for a non-porous pot (with a drainage hole) and regular bottom watering. You can quickly revive them - if they wilt - by sitting them in a dish of water until soil is again saturated and the leaves perk up. This plant is definitely a candidate for regular bottom watering, but make sure to leach the soil with a top watering every month or so if you always bottom-water.

Happy National Indoor Plant Week!

Tiny Plants: Bucephalandra ‘Black Pearl’

September 21, 2021

You don’t need to grow big to experience plant parenting or indoor gardening joy. Tiny plants are just as enjoyable (sometimes more!) and don’t need a lot of space or resources to thrive.

Like this tiny - yet VERY simple - little botanical semi-aquatic environment I created with a snippet of Bucephalandra ‘Black Pearl’ set on top of a small piece of bark. It sits in about 1/2” of rainwater inside a covered glass vessel, under a low intensity LED on a book shelf. It’s also started growing it’s own tiny moss forest.

Bucephalandra is a genus in the Araceae family (Aroids); and a genus of semi-aquatic plants that grow via a rhizome. They can be grown totally submersed, emersed, or mounted epiphytically inside tanks or terrariums. Naturally, plants grow on stones or rocks in streams in tropical forests and you'll find this is how they tend to thrive in indoor culture. There are tiny species and cultivars, such as this one, 'Black Pearl', and larger species. Their sizes vary widely, ranging from only 2 cm to 60 cm tall!

Just like other related aroids, Bucephalandra spp. produce spathe type flowers. In fact, they resemble an itty bitty peace lily flower. It's adorable. My plants haven't flowered, but that's most likely due to the lower light intensity. If I wanted them to flower, I'd increase the light intensity with a more powerful lamp, or run the lamp I have for longer. But, I'm quite happy with my little foliage specimen as it is, where it is, as of now.

To maintain this simple planting, all I do now and then is wipe out a bit of algae growth and add a bit of rain water. That’s IT. But this tiny plantscape brings me a lot of joy.

Happy National Indoor Plant Week!

Tiny Plants: Marcgravia umbellata

September 20, 2021

Shingling Vine for Terrariums and Vivariums

There is something irresistible to me about plants that creep and crawl in such a tight orderly tiny shingle vines do! This lovely specimen of Marcgravia umbellata (also known as monkey paws) has taken off from a couple of small stem cuttings I rooted in sphagnum moss inside this glass canister. I keep a lid on it.

These beauties will quickly take off inside terrariums, vivariums, or simple glass jars like this clinging to whatever is nearby - including the glass. It’s beautiful displayed all alone, but makes a wonderful mixed planting companion and an excellent background plant in vivariums. Just make sure to prune it regularly if it grows out of bounds. It's a tiny plant with big personality.

A bit of shingling vine botany

Now, a thing to know about shingling vines. All plants will go through as serious of changes developmentally as they morph from a seedling into a mature plant that can reproduce. For some plants that shift isn't outwardly noticeable, until you see buds or flowers. But for other plants there are distinct morphological differences that signal juvenility versus maturity. In many shingling vines the flat or quadrangular leaves that adhere to trees or other supports with aerial roots represent the the immature or juvenile growth phase of many vines that, once mature, will grow much larger and produce larger leaves that don't look much like the smaller shingling immature leaves. Marcgravia spp., which are a group of tropical flowering vines, fall into this category. So, the teeny orderly shingling leaves of the immature vines will eventually, but only under the right conditions and after time, shift into a mature phase with much larger foliage that does not shingle in this fashion. However, it's unlikely that in home indoor conditions, or in a terrarium, that your plants will make this shift.

ALSO, vines/stems can revert to their juvenile phase if they start growing out into the air with no support structure.

Marcgravia spp. are semi- or hemiepiphytic, meaning that some species may become fulling epiphytic after losing contact with terrestrial soil. But, seeds of the plant may also germinate in tree canopy...but may ascend to become terrestrial. Basically they can do both.

Oh, by the way Happy National Indoor Plant Week!

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