The Case for Growing Under LEDs — Reading Light for Agaves Through PPFD and DLI

On September 26, 2026, we gave a lecture titled “What Is Light to an Agave? — How Can Grow LEDs Bring Us Closer to the Light of Its Native Habitat?” at the UndergrounD AGAVE SEMINAR held at TITANOTA BASE. This article follows the flow of the slides from that day, rewritten as a readable piece with illustrations and sources.

The Bottom Line First

• We measure light with two numbers: Photosynthetic Photon Flux Density (PPFD), its intensity at any given moment, and Daily Light Integral (DLI), the total amount over one day. A good DLI target for growing is around 42, which corresponds to the annual average in the native habitat. Where conditions allow, some growers aim for 70–80.
• The color mix of sunlight reaching the ground is nearly the same in Mexico and in Japan. What Japan lacks is the “quantity” and “duration” of light in winter: in Tokyo, Japan, outdoor light in December and January is only about half that of the native habitat of Agave oteroi.
• Growth is a multiplication of water × temperature × light. Increasing light alone will not make a plant grow if water and temperature are lacking.
• Start by recording your light’s intensity (PPFD) and how many hours it is on, then calculate the DLI that is actually reaching your plant. With Agave Light, you can convert a lux meter reading to PPFD by dividing the reading by 54.

1. What Is Light to a Plant?

Light Is Both “Energy” and “Information”

Light plays two roles.

• Energy: Photosynthesis is the reaction that makes sugar from CO₂ and water, and light is its only power source. Even with water and fertilizer, a plant cannot build more body without light.
• Information: Plants read the color, amount, direction, and duration of light using dedicated proteins called photoreceptors. Red and far-red light are received by phytochromes, blue and UV-A by cryptochromes and phototropins, and UV-B by UVR8. Plants use this information to decide whether to stretch or stay compact, whether to open their stomata, and when to rest (Casal 2013).

PPFD: The Number of “Light Particles” Arriving Each Second

Light reaches a leaf as a stream of tiny particles called photons. Because photosynthesis proceeds one photon at a time, what matters to a plant is not how much energy the light carries but the “number of particles.”

PPFD (Photosynthetic Photon Flux Density) is the number of photons between 400 and 700nm that reach 1m² in one second. Its unit is μmol/m²/s. At noon on a clear day, it is roughly 2,000. Ultraviolet and far-red light are not included in this count.

If we compare light to rain, PPFD is the “rainfall intensity (mm/hour).” Because it is the intensity at a single moment, it changes constantly with the time of day, the clouds, and the distance from the light.

DLI: The Total Light That “Falls” in a Day

DLI (Daily Light Integral) is the total number of photons received in one day. In rain terms, it corresponds to “daily rainfall,” and its unit is mol/m²/day.

• DLI = PPFD × lighting time (hours) × 0.0036
• Example: At PPFD 1,270 (the center value for Agave Light 24W used at 40cm), running the light for 8 hours gives 1,270 × 8 × 0.0036 = 36.6 mol/m²/day
• Example: At PPFD 890 for 12 hours, 890 × 12 × 0.0036 = 38.4 mol/m²/day

On a graph, DLI is “the area under PPFD as it changes over time.” Sunlight forms a hill, weak in the morning and evening and strong at noon, while an LED forms a rectangle of constant intensity.

Even at a similar DLI, “strong and short” is not the same as “weak and long.” We recommend keeping a record of both the light’s distance and its lighting time.

Why We Measure in PPFD, Not Lux

Lux, which you can measure with a smartphone light meter, is a yardstick for “how bright something looks to the human eye.” It gives heavy weight to green through yellow, where the eye is most sensitive, and little weight to blue and red. Plants, on the other hand, make good use of blue and red photons too. As a result, grow lights strong in blue and red read dimmer in lux than they really are. Conversely, green reads high because it looks bright to the eye.

A Plant’s Body Is Made of “Air and Water”

By dry weight, about 96% of a plant’s body is carbon, oxygen, and hydrogen. All of the carbon comes from CO₂ in the air, and the oxygen and hydrogen come from CO₂ and water. The fertilizer nutrients taken up from the soil, such as nitrogen, phosphorus, and potassium, make up the remaining 4–5% (Epstein 1972; the proportions vary somewhat between plants).

In the 1640s, van Helmont planted a 2.3kg willow sapling in 90kg of soil and gave it nothing but water for 5 years. The willow grew to about 77kg, yet the soil had lost only 57g. The added weight had been built not from the soil but from air and water.

Photosynthesis Is the Reaction That “Turns Light Energy into Sugar”

Photosynthesis proceeds in the following two stages.

1. Light reactions: Light energy splits water (this is where oxygen is released) and is converted into “small packets of chemical energy” (ATP and NADPH).
2. Calvin cycle: Those packets are used to assemble CO₂ into sugar. This stage does not use light directly, but if the light reactions stop, it runs out of fuel within minutes.

Fertilizer Is the “Machinery,” Air and Water Are the “Materials,” Light Is the “Electricity”

It becomes easier to understand if you think of a plant’s body as a factory that makes sugar.

• Only a few percent of the light that arrives becomes part of the plant’s body. When this “electricity” runs short, nothing else you add will make the body grow.
• With too little fertilizer, there is too little machinery; with too little light, the machinery cannot run.
• Adding nitrogen while light is still lacking only builds more machinery that cannot run, so plants tend to become dark-colored and etiolated (leggy, stretched growth).
• Water carries nutrients to the leaves and sugars to the roots and new leaves. However, most of the water a plant absorbs is lost through transpiration, and only a small part becomes building material. Because agaves open their stomata only at night, they need just one-fifth to one-tenth as much water as ordinary plants to build the same amount of body.
• Agaves allocate the sugar they make to leaf fibers and to fructose polymers (fructans) stored in the core. A compact, tight rosette, thick leaves, and leaf teeth are all structures built from sugar.

Light as Information: Four Photoreceptors

Even at the same DLI (PPFD), leaf length, thickness, color, and stomatal behavior change depending on whether there is more red or more blue, whether far-red is mixed in at dawn and dusk, and how many hours of light and darkness there are. This is because the receptors use light signals to switch genes on and off.

Etiolation Is a Phytochrome Decision

In sunlight in an open area, the ratio of red (660nm) to far-red (730nm), or R:FR, stays nearly constant at about 1.15. In the shade of other leaves, this ratio drops to 0.05–0.7, because leaves absorb red and let far-red pass through. Phytochromes read this as “there is a competitor next door” and elongate stems and petioles. This is called the shade avoidance response (Smith 1982). The common saying that “evening sun makes plants stretch” comes from the fact that morning and evening light has a low R:FR of about 0.6. However, unless a plant is in the shade of other plants, this alone will not make it keep stretching.

Indoors, the main cause of etiolation is weak light (plants stretch in dim light even without a shade signal; Casal 2013). On top of that, incandescent light, and window light that passes through surrounding plants or curtains, are skewed toward far-red, so plants can mistake them for “shade.” With a plant grow LED providing light of the right intensity for long enough, plants will not stretch. Red light (660nm) with little far-red is the signal for an “open area.”

Blue Builds a Compact Rosette; UV-B Is a “Protect Yourself” Signal

• Under blue light, cryptochromes suppress elongation and push leaves to grow thicker and shorter.
• In 2025, it was confirmed that blue light also opens stomata and increases photosynthesis in an agave hybrid (Sartori et al. 2025).
• That said, more blue is not always better. The response depends on the combination of the proportion of blue and the light intensity, and sensitivity also differs by species.
• Through UVR8, UV-B prompts the epidermis to produce UV-absorbing compounds and suppresses elongation. The increase in reddish color and waxy bloom under strong light is part of this defense. At the right dose, it works as sunscreen; too much causes tissue damage.
• UV-B and UV-A/violet (around 415nm) are received by different photoreceptors. You cannot lump them together and say “UV makes the leaf teeth stronger.”

Reading “Duration”: The Internal Clock and CAM

Plants have an internal clock of about 24 hours, which they reset every day using “the time it gets light” as their cue. That light is received by both phytochromes (red) and cryptochromes (blue). In CAM plants, this clock supports the rhythm of “opening stomata at night to store acid (malic acid), then closing them during the day to turn it into sugar.” It has been shown in a different CAM plant (Aechmea) that light quality is involved in synchronizing day and night metabolism (Ceusters et al. 2014).

If you shift the lighting schedule from day to day, or strong light leaks in at night, the plant’s clock may be disrupted and its nighttime CO₂ uptake may drop. The basic rules for using LEDs are as follows.

• Your lighting hours do not have to match outdoor daytime. It is fine to turn the light on at night and off in the morning.
• Run the light for the same length of time, at the same time of day, every day.
• Plan the dark period as well, including stray light from neighboring lights and windows.

Note that most of what we know about photoreceptors comes from Arabidopsis and crop plants. What has been directly confirmed in agaves goes only as far as the stomatal response to blue light (2025). The response to light quality has so far been shown only in a CAM plant from a different family (Aechmea, in the pineapple family).

2. Agaves and Light

Agaves Need Light Too: How CAM Plants Work

Agaves open their stomata at night to take in CO₂, convert it into an acid called malic acid, and store it in their leaves. During the day, with their stomata kept closed, they release CO₂ from that acid and use light energy to turn it into sugar. In other words, an agave does not “photosynthesize at night”; it is a plant that “uses daytime light to process the CO₂ stored overnight.” How much light it receives during the day determines how much CO₂ it can take in the following night. There is also a phase in which the stomata open toward the end of the light period, and the response varies with the time of day and the condition of the plant.

Numbers Actually Measured in the Genus Agave

Agaves enter the range where “light is sufficient” at 20–30 mol/m² or more of light per day, and depending on the species and the age of the plant, they can use even more. However, no study has yet determined the optimum for Agave oteroi itself.

There is one more important point. When research papers say light is “sufficient,” they mean the plant “can grow (can take in CO₂).” If your goal is a firm, compact, tight rosette, we believe it takes more light than that. So from the next section on, we will consider the optimal amount of light, using the light of a well-known Agave oteroi locality as our benchmark.

3. Light in the Native Habitat: Oaxaca

Location and Climate of Oaxaca, Mexico

Agave oteroi was described as a new species in 2019. Its type locality is the basin of the Río Hondo, which flows along the border between the states of Puebla and Oaxaca, at an elevation of 975–1,160 m (Starr & Davis 2019). The Tehuacán-Cuicatlán Valley is a semi-arid region in the rain shadow of the Sierra Madre, with annual rainfall of 250–500 mm (concentrated from May to October). It is the region with the highest diversity of agaves in the world.

The light values were derived from NASA satellite data (NASA POWER, 2001–2020 average). Satellite values are averages over a grid cell roughly 110 km on each side, and that cell includes mountains as high as about 4,500 m. The native habitat on the valley floor may be brighter and warmer than these values.

As a rough guide, 6.5 hours of sunlight at 100,000 lux (PPFD about 1,850) gives a DLI of about 43, which reaches the annual average of the native habitat.

Monthly DLI in Oaxaca and Other Growing Regions

Oaxaca has a DLI of 35–48 throughout the year. Even in winter, it receives about as much light as Tokyo does in summer (35–39), with 11–13 hours of daylight every day.

Maximum PPFD at Noon

• At noon on a clear summer day, every site is at around 2,000. In winter, the value is determined by how high the sun rises.
• At winter noon, the native habitat reaches 1,430 under actual weather and 1,640 under clear skies. Winter noon in Tokyo is only 880, and no more than 1,040 even under clear skies.
• In the native habitat, winter is the dry season with few clouds, so under actual weather, winter is brighter than summer (1,170).
• These values are 1-hour averages, so momentary peaks are higher.

4. Light in Japan

• In summer, Japan’s DLI is on par with Oaxaca’s. The problem is October through March: in December and January, the DLI is 17–20, only half that of Oaxaca. Days are also about 2 hours shorter and temperatures are lower, which makes growing outdoors difficult.
• On an indoor windowsill, the glass, the angle of the light, and the distance into the room reduce light to anywhere from a small fraction to about half of outdoor levels. In practice, you should assume it is very difficult to give a plant light comparable to its native habitat indoors in winter without an LED.
• Compared with Oaxaca, Japan is hotter and more humid in summer and colder in winter.

5. Light in Countries Known for Agaves

DLI and cloud cover are NASA POWER averages for 2001–2020. Noon PPFD comes from the same NASA POWER source, using hourly data for 2025 (1-hour averages over the days within 10 days of the summer and winter solstices). All values are for a horizontal surface, outdoors, averaged over the grid cell (1°×1° for light, 0.5°×0.625° for weather). For Taiwan, we used the grid cell that contains Lize (麗澤園藝, Tianwei Township, Changhua County). Tokyo has the lowest annual average of the six sites: agaves in Japan are grown in the place with the least light among the world’s growing regions.

Temperature and humidity are grid-cell averages at 2 m above ground (about 55 km × 66 km), not local values for the valley or for urban areas. Elevation adjustments use a lapse rate of 0.65℃/100 m. The native habitat is a place with “plenty of light, but not hot”: even adjusted to the valley floor, it averages 22℃ for the year and 23℃ in July. Summer in Japan (26–27℃, humidity above 80%) is hotter and more humid than the native habitat.

• Day length: The lower the latitude, the smaller the change over the year. Oaxaca ranges from 11 to 13 hours; Tokyo, from 9.6 to 14.4 hours.
• UV-A: Increases roughly in proportion to total light; the native habitat receives about 1.5 times as much as Tokyo.
• UV-B: Increases sharply with elevation and sun height; the native habitat receives about twice as much as Tokyo.

Here is how each growing region compares.

• Lize, Taiwan: It gets only about 10–20% more light than Tokyo (33.0 vs. 28.8), but the winter dip is shallower (lowest month: 24), and it is still 17℃ in January. The reason production is based in Taiwan likely has more to do with “winter temperature” than with light.
• Bangkok, Thailand: The most stable of all, at 37–47 year-round. It is always hot, with little difference between day and night temperatures. Winter noon PPFD also holds at 1,700. The region gets frequent squalls.
• Arizona and Tehran: Regions with low humidity (20–50%) and large temperature swings. Summer light is stronger than in the native habitat (peak-month DLI of 58–61), while winter light drops to Tokyo levels. Plants there don’t suffer from stuffy, humid conditions under strong light because the air is dry. If you give the same light in Japan, you need to plan humidity and airflow together with it.
• Oaxaca: Plenty of light, yet not hot. The grid average is 16℃ for the year (at 1,995 m, including the mountains), but adjusted to the valley floor at 1,050 m, it is about 22℃ for the year, and even in the warmest months of April–May, about 26℃ with humidity below 60%. Summer in Japan (26–27℃, humidity above 80%) is more humid than the warmest period in the native habitat, and it does not cool down at night. In the native habitat, nights stay close to around 15℃, the temperature at which agaves readily take in CO₂ at night.

6. Spectra Around the World: Color Is the Same Everywhere

The shape of the visible part of the sunlight that reaches the ground is nearly the same from one country to the next. The differences come down to four things: quantity, UV, scattering, and time of day.

1. UV (especially UV-B) increases with altitude and with the height of the sun: Under clear skies, UV-B increases by +18±2% for every 1,000m of altitude, UV-A by +9%, and total solar radiation by +8% (Blumthaler et al. 1997). The native habitat (about 1,000m elevation, 18°N) receives more UV-B than Tokyo, Japan (40m, 36°N).
2. Ratio of direct to diffuse light: The more humidity, cloud, and aerosols there are, the more diffuse (scattered) light there is. Japan, Taiwan, and Thailand have soft light with faint shadows, while Arizona, Oaxaca, and Iran have direct light that casts deep shadows. Even at the same PPFD, light reaches the lower leaves and the center of the plant differently.
3. The red to far-red ratio (R:FR) does not change from country to country: In open areas during the day it is about 1.15, nearly constant regardless of latitude, season, or weather. In the morning and evening it is about 0.6, and in the shade of plants it is 0.05–0.7. What shifts this ratio is the time of day and the surrounding plants.
4. Time of day: The lower the sun, the longer its light travels through the atmosphere; blue is scattered away and the light turns redder. These morning and evening color changes are the same all over the world.

When we modeled clear-sky sunlight at noon, the photon shares were 27–28% blue, 35% green, and 36–37% red, nearly identical across the native habitat, Tokyo, Taiwan, and Arizona (SPCTRAL2 model; the inputs are elevation, water vapor, aerosols, and ozone, not field measurements). R:FR was also 1.1–1.2, with almost no difference between countries. What does differ is UV-B (about twice as high in the native habitat as in Tokyo) and the overall amount of light.

What an LED needs to reproduce is not “the color of each country” but “quantity and time.” Choose the color based on the plant form you want to grow.

7. The Case for Growing Under LEDs

Filling the Gap in Japan’s Winter Light

In Tokyo, Japan, the outdoor DLI in December and January is 17–20, about half that of the native habitat (35–48). By a window, it drops even further. The realistic way to create native-habitat light levels and an 11–13-hour day indoors is with LEDs.

That said, light alone does not solve everything. In a Japanese summer, temperature and airflow matter more than light; in winter, light and temperature are the main factors. Before adding more light, check that the roots are active and that the leaves are not getting hot.

Quick Reference: Distance and Lighting Hours (Agave Light 24W)

Bold values are the combinations that exceed Oaxaca’s annual average DLI (41.8).

• At 30cm, about 8 hours of lighting is enough to exceed Oaxaca’s light level.
• If you want to match the lighting hours to the day length of the native habitat (11–13 hours), we recommend using the light at 40cm.
• Choose a setting that suits the height of your grow shelf and your electricity costs.

Values are calculated from the published PPFD at the center. Electricity costs assume ¥31 (JPY) per kWh and a 30-day month.

This quick reference shows values for the Agave Light 24W. If you need stronger light, or want to use the light from a greater distance, the Agave Light 32W is also available.

Growth = Water × Temperature × Light (Nobel’s Environmental Productivity Index)

Nobel, a leading figure in agave research, showed that how much an agave grows can be predicted by multiplying “water index × temperature index × light index” (Nobel 1984). Each index is a value from 0 to 1, where 1 means that factor is not limiting growth.

• The factors are multiplied, not added. Even if light is 1, if the soil has dried out and water is 0.2, the overall value is 0.2 × 1 × 1 = 0.2.
• For A. deserti in its native habitat, the monthly production of new leaves closely matched this index (r²=0.93, a strong correlation).

The values in this table are hypothetical, chosen to illustrate the idea; they were not measured on Agave oteroi.

When “I changed my light, but the plant isn’t growing,” the cause is often that only the light was increased while the water and temperature indices stayed low. Growers often talk about “light, water, and airflow,” but research focuses on “light, water, and temperature.” When your agave room is dark, turning your attention to nighttime temperature is another useful angle.

The Order for Deciding Your Setup

1. Root environment: Give the plant strong light only after it has rooted well.
2. Measure PPFD at leaf level: Measure near the growing point (with Agave Light, you can also use your lux meter reading ÷ 54).
3. Lighting hours and DLI: Use the day length of the native habitat (11–13 hours) as one benchmark. Moving the light closer and shortening the hours is another option.
4. Watch leaf temperature and new leaves: Check for whitening and damage, and see how new leaves are unfolding.
5. Change one thing at a time: Do not change light, water, and fertilizer all at once.

If the plant is not growing, check whether the roots are active, whether the change from its previous environment is too large, whether the leaves are getting hot (if photoprotection is simply at work, that is not damage; if the leaves are hot, use a circulation fan to carry the heat away), and whether moisture and temperature are right.

Use Cases: Lighting Hours and Distance

We compared five ways our customers use their lights in terms of DLI, the area under the PPFD curve (PPFD × hours × 0.0036). All five charts share the same vertical-axis scale.

For comparison, Oaxaca’s annual average is 41.8, and a clear day there reaches 49.8. Some users grow their plants at a DLI of 70–80.

The stronger the light, the more closely you should check leaf temperature and watch new leaves for whitening or browning. When using strong light, move the lamp closer a little at a time to find the limit. Moving it close all at once can scorch the leaves.

Overlaying these values on the monthly DLI charts for each country gives the result below. The LED values stay the same regardless of season.

Agave Light Uses the Same Lux Conversion Factor as Sunlight

When we measured the spectrum of Agave Light and compared it with sunlight, the shapes were different (the LED has peaks), but the photon shares of blue, green, and red were nearly the same.

To help agaves grow compact, Agave Light has a spectral peak in blue and violet, as well as a peak in red, which is readily used for photosynthesis. Even so, it is designed so that the overall blue, green, and red proportions of its light are nearly the same as sunlight.

As a result, its ratio to lux (which is weighted by the sensitivity of the human eye) is also the same as for sunlight, so you can convert with PPFD ≒ lux ÷ 54 (53 in our measurements). For example, 100,000 lux corresponds to a PPFD of about 1,850. However, this conversion only works for lights whose spectrum is close to sunlight. Lights with strong red or blue have very different conversion factors.

Today’s Takeaways

1. Use PPFD and DLI as your measures of light: A good DLI target for growing is around 42. If your environment allows, try aiming for 70–80.
2. Growth = water × temperature × light: If any one of water, temperature, or light is lacking, things will not go well. Keep temperature in mind, too.
3. Try keeping a record of your growing environment: Record the light intensity (PPFD) and the lighting hours, and calculate how much DLI your plant is receiving. With Agave Light, you can calculate it as lux ÷ 54.

To begin, try recording just one thing: the amount of light at your plant’s position and how many hours the light is on.

What We Still Don’t Know

• The light saturation point of Agave oteroi (for now, we are borrowing values from related species)
• The optimal night temperature for Agave oteroi
• How red coloring, waxy bloom, and leaf teeth relate to the color and amount of light

The more records we gather from people growing these plants, the clearer these answers will become.

The Lights Used in This Article

• Agave Light 24W: For lighting a single plant from 30–40cm. Center PPFD directly below at 30cm: 1,790 (published value)
• Agave Light 32W: For shelves that need stronger light, or when you want to keep more distance. Center PPFD directly below at 30cm: 2,348 (published value)

References

• McCree KJ (1972) Agricultural Meteorology 9:191–216. Action spectrum of crop plants
• Thimijan RW, Heins RD (1983) HortScience 18:818–822. Conversion of light units
• Rizzini L et al. (2011) Science 332:103–106. UVR8
• Rai N et al. (2019) Journal of Experimental Botany 70:4975–4990. Interaction between cryptochromes and UVR8
• Epstein E (1972) Mineral Nutrition of Plants. Wiley. Elemental composition of plants
• van Helmont JB (1648) Ortus Medicinae. The willow experiment
• Zhu XG, Long SP, Ort DR (2008) Current Opinion in Biotechnology 19:153–159. Theoretical efficiency of photosynthesis
• Emerson R, Lewis CM (1943) American Journal of Botany 30:165–178. Quantum yield of photosynthesis
• Evans JR (1989) Oecologia 78:9–19. Leaf nitrogen and photosynthesis
• Casal JJ (2013) Annual Review of Plant Biology 64:403–427. Photoreceptors and the shade avoidance response
• Kinoshita T et al. (2001) Nature 414:656–660. Phototropins and stomata
• Jenkins GI (2017) Plant, Cell & Environment 40:2544–2557. UVR8 review
• Smith H (1982) Annual Review of Plant Physiology 33:481–518. R:FR and the shade avoidance response
• Holmes MG, Smith H (1977) Photochemistry and Photobiology 25:533–538. R:FR during the day and at dawn and dusk
• Snowden MC, Cope KR, Bugbee B (2016) PLOS ONE 11:e0163121. Responses to blue and green light
• Sartori HL et al. (2025) Theoretical and Experimental Plant Physiology 37:31. Agave hybrids and blue light
• Ceusters J et al. (2014) Journal of Experimental Botany 65:3705–3714. CAM and light quality
• Woodhouse RM, Williams JG, Nobel PS (1980) American Journal of Botany 67:1179–1185. Light interception and nocturnal acid accumulation in A. deserti
• Nobel PS, Valenzuela AG (1987) Agricultural and Forest Meteorology 39:319–334. A. tequilana
• Nobel PS (1988) Environmental Biology of Agaves and Cacti. Cambridge University Press
• Nobel PS (1984) Oecologia 64:1–7. Environmental Productivity Index (EPI)
• Nobel PS, Hartsock TL (1986) Oecologia 68:181–185. Predicted vs. measured productivity of A. deserti
• Nobel PS (1991) New Phytologist 119:183–205. CAM productivity and water-use efficiency
• Niechayev NA et al. (2019) Journal of Experimental Botany 70:6549–6559. Light saturation point of A. americana
• Starr GD, Davis TJ (2019) Cactus and Succulent Journal 91:134–143. Description of Agave oteroi
• Blumthaler M, Ambach W, Ellinger R (1997) Journal of Photochemistry and Photobiology B 39:130–134. Altitude and UV
• Bird RE, Riordan C (1986) Journal of Climate and Applied Meteorology 25:87–97. Solar spectral model SPCTRAL2
• Kromdijk J et al. (2016) Science 354:857–861. Photoprotection
• Nishiyama Y et al. (2001) EMBO Journal 20:5587–5594. Photoinhibition and repair
• NASA POWER (power.larc.nasa.gov) Climatology 2001–2020 / Hourly 2025
• 気象庁 平年値 (Japan Meteorological Agency, climatological normals; Tokyo 1991–2020) / Kew POWO / UNESCO Biosphere Reserves
• AgaveLives: Agave Light 24W/32W published values, measurements with HPCS-330P (2026-09-25), lecture notes (2026-09-08)

All figures were created by AgaveLives from public data and our own measurements, and all photos were taken by AgaveLives.