Growing Bamboo from Seed

How to Grow Bamboo from Seed

The instructions provided below reflect our recommendations for successful bamboo seed germination indoors. These step-by-step processes and procedures for germinating bamboo seeds in a controlled environment have consistently proven to successfully grow bamboo plants from seeds. (Please also see When to Germinate Bamboo Seeds for helpful guidance to determine typical timelines from seed germination to planting in-ground.)

 

Seed Storage

Immediately store your bamboo seeds in your refrigerator in the original shipping envelope until you are ready to germinate them. Most bamboo seeds will retain viability for up to a year, and many will remain viable for up to two years. Only a very few species of bamboo seeds are known to lose all viability within months of harvest, and for that reason those seeds are not harvested for commercial sale.

While it's not the norm, we have successfully test germinated Gigantochloa bamboo seeds that were stored under refrigeration for three years post-harvest. At 3 years, the germination rate was significantly reduced, yet there were still some viable seeds. Never underestimate Mother Nature! 

 

How to Germinate Bamboo Seeds

Carefully peel away and remove the fibrous outer bract from the larger bamboo seeds (eg Phyllostachys, Dendrocalamus, Bambusa, etc.). Some find it easier to wear nitrile gloves to better grasp the seeds, or to use needle-nose tweezers to gently peel away the seed bracts. Discard the bracts. (While we've observed enhanced germination by removing the outer bracts from the comparatively bigger seeds for Fargesia angustissima bamboo, we have not observed a demonstrable advantage in removing the bracts from the smaller seeds for other  Fargesia varieties. You may wish to test both methods to see which method works best for you.)

Soak the bamboo seeds: In a bowl or jar, mix 1 Cup warm (NOT hot) water and 1 Tablespoon hydrogen peroxide 3% concentration. Add the bamboo seeds, cover, and soak the seeds undisturbed for 24 hours in a warm (65F+) location. Gently strain and rinse the seeds with warm water. Discard the soak solution. 

The seeds for many bamboo varieties will begin germinating very quickly, and the emerging roots and stems are extremely delicate. When handling the seeds, be extremely gentle and avoid disturbing the wider base end of the seed.

Prepare the bamboo seed germination medium

We have tested various germination mediums, and find that (1) vermiculite, (2) paper towels/cotton batting, and (3) inert seeding mix are the three optimal methods, in order of our preferred germination method.

Vermiculite method: We have best results when using plain vermiculite as the germination medium. Vermiculite is inert, and the absence of biological components significantly reduces the incidence of molds, fungi, and other contaminants.

Vermiculite is also a superior medium for the quickly developing bamboo species that generate aggressively expansive roots early in the germination process. If the developing roots become embedded in paper towels or cotton batting, it can be challenging to manually extract them without causing injury to the seedling.

The one downside to using vermiculite germination medium is that the color and texture makes it a bit more difficult to see the first signs of germination. However the benefits of using vermiculite far outweigh this minor and temporary issue. If you are having difficulty assessing germination progress with the naked eye, take some pics of the seeds with your phone and then enlarge the image on screen to easily identify swollen buds and emerging roots and stems.

When using vermiculite as a germination medium, start with a vermiculite:water mix of approximately 2:1. You want the vermiculite to be thoroughly moistened, but without a sheen of visible water in your germination tray. Press the seeds only slightly into the pre-moistened vermiculite, spacing about 1" between seeds. Vermiculite absorbs moisture, so lightly mist daily to ensure the top layer of vermiculite that is in direct contact with the germinating seeds remains moist, but not sodden, throughout the germination process. 

Paper towel method: Layer moistened paper towels/cotton batting in a container with a vented lid and place the seeds atop the paper/cotton medium, spaced about 1/2" to 1" apart.

We find that using layers of moistened paper towels or cotton batting provides much better results than using an organic soil-based mix for seed germination. Our experience demonstrates that the paper towel method consistently provides superior initial germination results, with greatly reduced mold/fungus issues.  

Seed mix method: Alternatively, use a commercial, non-soil seeding (not potting) mix, or make a mixture of 1 part peat moss, 1 part coir, and 1 part vermiculite (for  enhanced moisture retention) or perlite (for enhanced aeration). Moisten the mixture until you can grab a handful and just barely squeeze out a drop. Distribute the premoistened seeding mixture into your germination trays, lightly pressing each seed onto the surface of the seeding mixture. Do not cover the seed.

We do not recommend using peat pots/pellets as they are notorious for encouraging fungal growth, they provide poor air circulation, and they often do not fully disintegrate until long after the seedling roots become over-crowded which compromises viable root and plant growth and development. While some recommend manually tearing/breaking up the peat pots before re-planting in soil to allow better root development and expansion, we find this to be unnecessary additional work and it risks transferring into the re-potting soil any pre-existing mold/fungus already growing on the peat pots.

In summary, use vermiculite, paper towels/cotton batting, or inert seeding mix for germinating your seeds. Do not use organic potting soil, or peat pots, Jiffy pots, and the like.

Bamboo seed germination: Place the lid on the container and move the container to a spot where it won't be disturbed, it receives sufficient full spectrum natural light (but not direct sunlight), and the temperature remains constant between 68-78°F (20-25°C), with 75°F (24°C) considered optimal for most bamboo seeds. Fargesia seed germination in particular can be adversely affected by excessive heat, so maintain consistently moderate temperatures well within the recommended range.

A seed tray heat mat is recommended to maintain consistent temperatures during seed germination. Consider planting only seeds of one type of bamboo in each tray, as different bamboo species germinate and sprout at different rates, and the process of removing/repotting seedlings might disrupt other seeds in different stages of germination. Also, some seeds (such as Moso) are generally more prone to fungus/mold and maintaining some physical separation between seed varieties helps prevent cross-contamination.

Remove the lid for a minute or two daily to give the plants fresh air. Regularly moisten -- but do not oversaturate -- the paper towels/seeding mix during this time if it has begun to dry out. We prefer using a quality hand mister rather than pouring water directly onto the medium. Replace the lid after you have replenished moisture.

We have experimented with both vented and unvented lids, and see no discernible difference between the two, given that we're regularly lifting the germination tray lids and introducing fresh oxygen each time we evaluate germination progress and/or replenish adequate humidity.

Sprouting bamboo seeds: The bamboo seeds with characteristic fast germination (such as the tropical and subtropical Dendrocalamus) may sprout within a few days, and the bamboo seeds with longer germination times (such as some of the cold hardy mountain Fargesia and Borinda which can require 6+ weeks to germinate) will take longer to sprout, depending on the species, variety, and conditions. (You'll find average germination times on each bamboo seed listing page.) It's usually pretty easy to spot the telltale signs of early germination on most seeds, although the smaller Fargesia seeds sometimes require magnification to identify initial germination.

During germination tests we regularly document progress with photos taken with a mobile phone, and enlarge the images as needed to closely examine the seeds for early signs of germination. We highly recommend taking your own photos and keeping notes during your germination process, as it's very easy to forget or confuse important developmental milestones, especially when germinating a variety of different seeds. Taking pics also makes it much easier to identify and track when it's time to transition seeds from the germination tray onto seedling mix, and to conduct ongoing troubleshooting for any issues as they arise.

Many cold hardy mountain bamboo seeds (such as Fargesia) are genetically predisposed to cooler environmental temperatures, and it's important to maintain moderate heating throughout their germination process without over-heating.  Aim for temps between 70-75F. Because Fargesia seeds typically take longer to germinate, we recommend using inert vermiculite or paper towel media. If you opt for soil medium we recommend using only inorganic, non-soil (ie, coir, moss) germination media to reduce mold/fungus which is far more likely to occur in nutrient-rich, organic soil-based media. Dense soils also tend to restrict light and oxygen, and increase the potential for moisture retention and oversaturation. 

Do not apply systemic fertilizer to germinating seeds, and never before the development of plant roots sufficient for uptake. For seeds in the initial stages of germination that do not yet have roots, it's not at all productive to apply systemic fertilizer which requires uptake via roots. The cotyledon provides all the nutrients that a viable seed requires for seedling production from initial germination through development of the first set of leaves. Premature application of chemical fertilizing agents also runs the risk of accumulating excessive nitrogen or other caustic elements into the germination medium that may be counterproductive for naturally phased, healthy seed germination and seedling development.

The overuse of systemic fertilizers on seedlings can artificially accelerate early culm growth/height out of balance with natural leaf production and development, resulting in generally weakened seedlings and plants. Using a good quality seeding mix for newly germinated seedlings and a quality soil mix for repotting more mature plants, and maintaining optimally consistent growing conditions, should be sufficient to nourish and support balanced, incremental development throughout the early growth stages from initial seedling to established young plant.

Transplant the bamboo seedlings: After the bamboo seeds have fully germinated on the germination medium and display healthy roots and first leaves, it's time to transition the germinated seeds onto organic potting soil mix in individual cups or pots.

Transplant the seedlings from the germination medium into small individual pots filled with quality seeding mix after the seedlings have developed healthy roots and produced primary first leaves. The growth of newly germinated seedlings and the schedule to transplant them from germination medium to potted soil varies depending on the species and growing conditions. General rule of thumb is to place newly germinated seeds onto seeding mix when they have good visible root development, and good culm development proportional with fully formed primary leaves. If you have newly germinated seedlings tall enough to come in contact with the germination tray cover, but they do not yet display a primary leaf or two, gently move the tray to a taller container and give them a little more time to produce leaves before transplanting them from the germination medium onto seeding mix.

Remain watchful of accelerated root development, especially in the tropical/subtropical giant bamboo varieties (eg, D. asper, D. membranaceus, and D. giganteus), which if left for too long on paper towel/cotton media might result in some roots becoming embedded in the media. This will require some very gentle teasing of the roots away from the media with needle tweezers when it comes time for transitioning the seedlings onto seed mix. Damaging newly formed roots can negatively impact seedling development, so emphasis on gently.

Depending on your climactic conditions, you can keep the potted seedlings indoors or in a controlled greenhouse until conditions are optimal to begin incrementally hardening the potted seedlings outdoors for eventual planting in the ground or in planters after all danger of frost has passed. 

Please also see When to Germinate Bamboo Seeds for helpful guidance about typical timelines from seed germination to young bamboo plants ready to transition out of doors.

 

Germination Rates

Because each person's growing environment, conditions, equipment, practices, and expertise are unique and completely out of our control, we can not guarantee germination. You will sometimes see germination rates published for commercial seeds; these rates are typically based on a single germination event conducted in scientifically controlled, pristine laboratory conditions at peak seed viability, which means the rates are often misleadingly inflated, which encourages unrealistic expectations.

Consider the fact that even the most tightly controlled laboratory environment simply can not exactly replicate the variables of seed germination and growing conditions in the wild. Also consider the fact that it's simply not possible to exactly replicate any one horticultural germination test. And then consider the fact that even if 100 people follow the same germination instructions, there will be countless variables at play in the 100 different growing environments that can either increase or decrease germination success. One person might think there's too much risk in germinating seeds; the next person eagerly embraces the  adventure and the challenge.

Even in optimal conditions, it's a given that not all seeds that germinate will survive the seedling phase, and among those that do, there are always some that fail to mature into robust representatives of the species. That's how nature works. Subsequently, a stated  "germination rate" is unlikely to be an absolute baseline for expected germination success outside of commercial greenhouse conditions or for long-term viability through maturity. At most, it represents a one-off event in one place at one time with a non-reproducible selection of individually unique and highly variable seeds.

Like all embryos, not all seeds are biologically viable when they are originally created by the mother plant. Gently removing the exterior bracts from bamboo seeds after soaking them and prior to placing them in the germination medium helps to visually identify non-viable seeds (ie unformed, deformed, dessicated, etc.). Removing the outer seed bracts also reduces the amount of decaying organic matter that can be an ideal breeding ground for unwanted molds and fungi, enhancing your germination efforts overall. We have found that the bamboo seeds with their bracts removed consistently germinate more quickly, and with less mold/fungus issues, than seeds germinated with their bracts intact.

Like all other seeds, different types of bamboo seeds have widely varying germination rates, with the Fargesia and other higher elevation mountain/cold hardy bamboo types often requiring longer germination periods, typically 6+ weeks. We highly recommend using paper towel/cotton batting rather than a soil medium for these slower germinating seeds, because the former provides more opportunities to easily observe and appropriately adjust germination conditions over the longer period of time needed to germinate. Any seed buried out of sight in over-saturated, contaminated, or otherwise compromised soil for an extended period of time has a significantly higher rate of failure.

Appropriate and consistent germination procedures and care are key to all seed germination, with genetic and temporal seed viability and optimally maintained temperature, moisture, light, oxygen, nutrients, and environmental hygiene the most critical elements.

Begin the germination process as soon as possible after receiving your bamboo seeds to ensure optimal seed freshness and viability. Always store seeds in a cool, dry, air tight location away from direct light until you are ready to germinate them -- in your refrigerator is optimal. With properly sterile, airtight, refrigerated storage conditions, most viable bamboo seeds will remain so for a year, with some retaining viability for up to 18 to 24 months. 

Troubleshooting Checklist

We have found that the most common reasons for difficulties with seed germination include:

• Incorrect, insufficient, or inconsistent temperatures. A seed germination mat can be very helpful in maintaining optimal germination temperatures. Once your seeds have germinated, reduce and only use supplemental heat as needed to replicate optimal natural temperatures and environmental conditions for each particular bamboo plant species/variety.
• Inconsistent moisture -- either oversaturation or insufficient moisture.
• Excessive mold/fungus, either already present in the soil/medium, on surfaces, or airborne. 
• Insufficient full spectrum light (overly tall, weedy seedlings; wan, pale yellow stems and leaves), or over exposure to direct sunlight (browned, dry appearing, curled leaf tips and surfaces).
• Placement beneath excessive cover of soil or other materials that prevent natural growth and expansion of roots, stems, or leaves.
• Low or non-existent air flow that deprives seeds of sufficient oxygen.

All of the above listed recommendations and troubleshooting tips will best support successful germination.

Please see When to Germinate Bamboo Seeds for information about timing your indoor seed germination efforts for optimal planting outdoors.

 

And Now a Word About that "Floating Seed" Myth

No matter how many times the myth is repeated on the Internet, it's still not true that if a seed floats when placed in water, that's a surefire indicator that it's not viable. Some seeds may float because they're hollow, lightweight, or have air pockets. Seeds can have different sized and distributed air pockets depending on the species. Impermeable seed coats can also contribute to buoyancy. Fibrous bamboo seed husks, such as those encasing the majority of bamboo seeds, are inherently buoyant.

There are just as many reasons why viable seeds might float as there are reasons why some seeds simply aren't viable, and very few of those reasons are demonstrated by a seed's relative buoyancy. Mother Nature has countless ways to diminish or extinguish seed viability, and while a visually damaged, defective, or desiccated seed might quickly reveal diminished viability, there are many other less visibly obvious reasons -- such as genetics, disease of the mother plant, environmental conditions, climatic trends, seed immaturity -- why any one seed may never successfully germinate. A bamboo seed's buoyancy in water is a highly unreliable indicator.

We have conducted numerous "seed flotation" tests and without exception,  (1) most bamboo seeds with intact bracts initially float, and (2) after soaking for 24 hours, most bamboo seeds with their bracts removed sink, and (3) we've observed no quantifiable association between a bamboo seed's germination potential and whether it floats or sinks at any given time. 

 

 

Germinating Flower Seeds and Ornamental Grass Seeds

For germination instructions for flower, grass, and other seeds, please see the excellent online reference Seed Germination Theory and Practice, by Dr. Norman C. Deno. This is a free PDF of his book that covers germination of most every imaginable seed type. His encyclopedic germination guide is provided courtesy of the USDA, and the detailed information about seed germination contained in this classic reference is unmatched.

 

 

 

 

 

 

 

Rev. 100824