Growing and Harvesting Kratom in a Tropical Climate: Legal Basics, Shade and Propagation (Part 1 of 2)

Kratom_4U · October 16, 2026, 4:48am

Where this applies (status as of October 2026). Kratom is illegal or controlled in Malaysia, Singapore, Vietnam and Myanmar, and restricted in several other countries. This guide is only for places where growing kratom is legal. Check your local law before you plant, propagate or keep any kratom material.

Kratom grows well in Southeast Asia and is legal to grow in Thailand. Very little controlled research exists on how to grow it. This guide covers what two US studies actually measured, on shade and on rooting cuttings. It keeps those results separate from common practice that has no published support.

This guide is about growing the tree, not about using it. How kratom acts on the body is covered in Kratom: Botany, Alkaloids, and How It Actually Works. The risks are covered in Kratom Risks: What the Death Reports Show, Liver Injury, Dependence and Withdrawal. Nothing here encourages you to consume kratom.

Kratom law in Thailand: the short version

In Thailand, kratom has been legal since 2021–2022. Rules on advertising and food were still changing in 2026 (see Thailand’s Criteria for Food Advertising B.E. 2569: The July 2026 Rules for Cannabis and Kratom). The main law is the Kratom Plant Act B.E. 2565 (2022), in force since 27 August 2022. Under this Act:

You need no licence to grow kratom for personal use.
You need a licence from the ONCB (Office of the Narcotics Control Board) to import or export kratom leaf.
Selling kratom is banned to people under 18 and to pregnant or breastfeeding women.
Consuming kratom mixed with narcotics, psychotropic or other specified substances is banned. This covers the mixed drink known in Thailand as “4x100”. Promoting such mixtures is also banned.

Processed food, drinks or health products that contain kratom need a product licence from the Thai Food and Drug Administration (Thai FDA, อย.). Check with the Thai FDA whether your product needs approval before you sell it.

This summary is not enough to rely on. For details and penalties, read Kratom Law in Thailand After 2021, and Across the Region. Then write down which case fits your plan: personal growing, selling fresh leaf, or making a processed product.

The plant: a coffee relative that grows under taller trees

Kratom (Mitragyna speciosa) is a tropical evergreen tree. It belongs to the Rubiaceae, the plant family that includes coffee. For a grower, this is the most useful single fact. Like coffee, kratom is an understorey species: a plant that grows beneath the canopy of taller trees.

The native range covers southern Thailand, peninsular Malaysia, Indonesia (especially Kalimantan, on the island of Borneo) and the Tanintharyi Region in southern Myanmar. A plant being native to a country does not make it legal to grow there. See the box at the top.

In cultivation, kratom is a long-lived perennial tree, not an annual crop. You plant once and harvest leaf for many years. That makes the economics very different from cannabis, which is replanted every cycle. A poor choice of site or shade stays with you for years.

Before you plant, list the partly shaded spots you already have. Examples are ground under rubber or fruit trees, or the edge of an orchard. The next section explains why shade matters.

Light: the best-studied factor

Light is the part of kratom growing with the best evidence. The result goes against most growers’ instincts: more shade gave more leaf and more alkaloid.

The study was published in the journal PLOS One in 2022. It was run by a research team led by Zhang M. at the University of Florida. The team grew young plants, raised from cuttings in containers, under three light conditions:

Full sun in the field
A greenhouse without shade cloth (about 40% of full sun)
A shaded greenhouse (about 25% of full sun). Shade cloth was laid over a polycarbonate roof, a rigid clear plastic sheeting.

Growth: greenhouse plants grew far more

Compared with plants in full sun, greenhouse plants showed:

Height growth 93–114% greater
Width growth 53–57% greater
Total leaf area 118–160% greater
Leaf number 54–80% greater
Total leaf dry mass (leaf weight after drying) 89–91% greater

In the most shaded greenhouse, leaves were 69% larger than on plants in full sun.

Alkaloids: shade raised concentration as well

Alkaloids are nitrogen-containing compounds made by the plant. Mitragynine is the main alkaloid in kratom leaf. The study measured each alkaloid as a percentage of dry leaf mass. Several were higher under shade:

Mitragynine: about 40% higher in the shaded greenhouse than in full sun
Paynantheine: about 35% higher
Corynoxine: roughly double

Four other alkaloids did not change significantly with light: speciociliatine, mitraphylline, corynantheidine and isocorynantheidine.

Shaded plants had more leaf, and each gram of leaf held more mitragynine. As a result, mitragynine yield per plant nearly tripled under the shaded treatment. Corynoxine yield per plant was 116–298% greater.

In most crops, shade gives more leaf but dilutes the compound you want. In this trial, shade raised both. The researchers concluded that growers should use low light wherever they can set it up. Their stated aim was the most leaf and the highest total alkaloid content in that leaf.

Two limits of this study

First, the study compared field with greenhouse, not light alone. A greenhouse also changes wind, humidity and vapour-pressure deficit (VPD: how strongly the air pulls water out of leaves). The paper reports similar average temperatures in both places but no humidity data. So some of the difference may come from these other factors rather than from light.

Second, the plants were young plants in containers, raised from cuttings in Florida. They were not mature trees in Thai orchards.

What this means for a grower in Thailand

Kratom looks better suited to agroforestry than to open-field monoculture. Agroforestry here means intercropping: growing kratom as a second crop under an existing tree canopy. Monoculture means a single crop in full sun. If you have rubber, fruit trees or a shaded plot, that is a reasonable site for a trial.

If you plant in the open, start by cutting light by 60–75%. That range matches the two greenhouse treatments in the study. Treat it as a starting point to test, not a proven best level.

Translator’s note: Lowland Thailand often reaches 30–35 °C in the hot season. The Florida study reported similar average temperatures in field and greenhouse, so it tells you nothing about heat stress. Shade net is sold by shading percentage, so you can choose a net in the 60–75% range. A closed plastic house in Thai sun can get much hotter than the outside air, so keep the sides open for airflow. Start small. Plant a few trees under shade and a few in the open, then record height and leaf count every month for the first year. This shows whether the Florida result holds on your site before you commit a whole plot.

A cheaper way to check whether plants have adapted to shade

The study also tested a SPAD meter. This handheld device clips onto a leaf and estimates chlorophyll by measuring light passing through it. The leaf is not cut or damaged. SPAD readings matched lab-extracted chlorophyll fairly well (r² = 0.68, on a scale where 1 would be a perfect match).

Field plants had 17–23% less total chlorophyll than greenhouse plants. Leaves contain two forms of chlorophyll, a and b. Shaded plants had a lower a-to-b ratio, which is the typical sign that a leaf has adapted to shade. A SPAD meter is a faster, cheaper field tool than lab tests for checking whether plants are adapting as intended.

Translator’s note: SPAD meters are uncommon on small Thai farms. You can ask a university agriculture faculty or your provincial agricultural office whether you can borrow one. Mark the same leaves on shaded and sun plants and read them once a month. If shaded plants read higher than sun plants, they are behaving as in the study.

Propagation: why cuttings fail, and what improves them

You can grow kratom from seed or from cuttings (stem pieces rooted into new plants). Kratom cuttings are known to be hard to root. A 2025 study in the journal Frontiers in Plant Science, by a team led by Zhang M., measured how hard and tested ways to improve it.

Aeroponics against a mist system

The study compared two methods:

Aeroponics: cutting bases hang in the air inside a closed chamber, sprayed with a fine mist of nutrient solution. This was done indoors.
Greenhouse mist system: cuttings stand in a rooting medium on a bench, and nozzles spray fine water over them.

Aeroponics rooted 85–92% of cuttings in both seasons tested. The mist system rooted anywhere from 7% to 98%, depending on the season. In the worst season, more than nine in ten mist cuttings failed. The researchers described aeroponics as consistently high and the mist system as strongly variable from season to season.

Day length: 14 hours gave the most roots

Photoperiod means the number of hours of light per day. The team tested 10, 14 and 24 hours. The share of cuttings that rooted was similar in all three. But 14 hours produced the most root growth:

Total root length was 92% greater than at 10 hours, and 18% greater than at 24 hours.
Projected root area and root surface area were also higher.
The root crossing number was higher too. This counts how often roots cross each other in a scanned image, a rough sign of how branched the roots are.

At 24 hours, cuttings rooted slightly sooner.

In the native range, natural day length stays at about 11–13 hours all year. So cuttings under natural light alone never get a 14-hour day. You need supplementary lighting to copy this result.

Rooting hormone: the study dose is not a dip dose

Rooting hormones are synthetic auxins, plant hormones that trigger root formation. Two common ones are IBA (indole-3-butyric acid) and NAA (naphthaleneacetic acid). In the aeroponic system, the team added 5 mg/L IBA plus 2.5 mg/L NAA to the nutrient solution. The cutting bases were exposed to it continuously for weeks.

That continuous dose cannot be compared with commercial quick dips or powders. Those are applied once, at roughly 1,000–8,000 ppm. In water, 1 mg/L is about 1 ppm, so the study dose was hundreds to thousands of times weaker. A dip product used at 5 mg/L would almost certainly fail. If you use a commercial rooting product, follow its own label.

In the study, hormone increased the number of roots in aeroponics. It had little effect on other root measurements, and little effect in the greenhouse mist system.

Translator’s note: In Thailand, buy rooting products through an official distributor and use them only at the label rate.

Cultivars differ a lot

Cultivar	Rooting, aeroponics	Rooting, greenhouse mist	Losses to Fusarium (aeroponics)
MR-Malaysian	71–75%	32–38%	~11%
DR-Bumblebee	57–60%	17–23%	~5%
Hawaii	~40%	3–6%	~28%

Roots started to form after roughly 3–5 weeks. This timing did not differ significantly between cultivars. These names are US trade names, not Thai types. Part 2 explains what is known about Thai varieties.

Disease: Fusarium

Fusarium is a fungus that rots stems and roots. In the study, severe Fusarium infection led the researchers to discard 5–28% of cuttings by week 4, depending on cultivar. It is a hygiene problem, so keep tools, rooting media and water clean.

Timeline

Aeroponic cuttings had fully developed roots by week 6. In the team’s greenhouse mist trials, rooting took 8–10 weeks.

If you do not have an aeroponic system

Most growers do not have one, but the findings still help in three ways:

If your mist cuttings succeed in one season and fail in another, the method itself probably causes it, not your technique.
The likely fix is steady oxygen and moisture around the cut stem. A simple, low-cost aeroponic or well-aerated setup may pay for itself in cuttings that survive.
Give cuttings 14 hours of light a day, using lamps to extend natural daylight.

Translator’s note: Four Thai conditions change this advice.

Power cuts. In aeroponics, stem bases hang in air. If the pump stops, they can dry out fast. Put the pump and timer on a backup power supply, such as a battery unit or UPS (uninterruptible power supply), or plan a manual misting backup. Use a timer that keeps its settings during an outage, so the 14-hour day is not cut short.
Heat. At 30–35 °C, the water in a closed system warms up, and warm water holds less oxygen. Shade the unit and check water temperature. The forum topic Running Hydroponics at 31 °C Reservoir Temperature covers the same problem for cannabis.
Rainy season. High humidity favours fungi such as Fusarium. Disinfect tools between batches, use fresh rooting medium, and do not reuse old water.
Where cuttings come from. Cuttings or young plants bought from another farm can bring pests and Fusarium. They may also not be the type on the label. See the mother tree if possible. Keep new material apart from your own plants for a few weeks before it goes near your stock.

Keep a simple record for every batch of cuttings: date, method, hours of light, number rooted and number lost to rot. After two or three batches, you will see whether season, method or disease is your main problem.

Sources: Zhang M, Sharma A, León F, Avery B, Kjelgren R, McCurdy CR, Pearson BJ. “Plant growth and phytoactive alkaloid synthesis in kratom [Mitragyna speciosa (Korth.)] in response to varying radiance.” PLOS One 2022;17(4):e0259326. doi:10.1371/journal.pone.0259326; Zhang M, Montanez C, Pearson BJ, Li Y, Chen J. “Aeroponics enables consistent cutting propagation of kratom (Mitragyna speciosa): impacts of photoperiod, cultivar, and rooting hormone.” Frontiers in Plant Science 2025;16. doi:10.3389/fpls.2025.1650327 (the correction doi:10.3389/fpls.2025.1697035 changes figures only); Kratom Plant Act B.E. 2565 (2022), published in the Royal Thai Government Gazette 26 August 2022, in force 27 August 2022; Tilleke & Gibbins, “Thailand’s New Legal Framework for Kratom” (2022) and “Thailand’s Updated Guidelines on Kratom in Food and Herbal Products” (2024).