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“Restoring the Perception Around Peat” was released in the January issue of GrowerTalks. Susan Parent from PTH's Grower Services team contributed to the cover articlea s a follow-up to the Grower Talks webinar she did and provides some well needed insight to harvesting, restoration and sustainability of peat moss in Canada.
How do you choose the right mycorrhizal product for better business
When it comes to competitive markets, the cannabis industry is up there. To increase profitability, growers are trying to find their edge. Most businesses and cannabis lovers want to discover a way to produce better quality cannabis at a reasonable cost. But how?
This is when active ingredients come in. Active ingredients, such as mycorrhizae, offer incredible advantages for your culture, and ultimately for your business, which should not be neglected.
This is when active ingredients come in. Active ingredients, such as mycorrhizae, offer incredible advantages for your culture, and ultimately for your business, which should not be neglected.
Catalogue 2021-2022: Here it Comes
We are pleased to share with you our 2021-2022 PRO-MIX Professional Product Catalogue. Be the first to virtually get your hands on it in the new Toolbox section of our website.
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MYKE® ONLINE TRAINING
Refresh your MYKE® knowledge and train your new staff members on the benefits of of using MYKE®! Use the link below to access the 5 short videos. The trainings are easy, informative, and very helpful!
Photoperiod and flowering
Floraldaily - Publication date: Thu 14 Apr 2022
One of the most important environmental factors affecting flowering induction is Photoperiod. Photoperiod is defined as the time plants are exposed to light in a daily cycle.
Plants can be classified based on photoperiodic response in day-neutral, short-day and long-day plants. Day-neutral plants flower at the same time irrespective of the photoperiod. Short-day plants are plants that require a photoperiod shorter than a specific threshold (called ‘critical photoperiod’) to initiate flowers (qualitative short-day response) or plants that flower initiation is accelerated by shorter photoperiods (quantitative short-day response). Long-day plants are plants that require a photoperiod longer than a specific threshold to initiate flowers (qualitative long-day response) or plants that flower initiation is accelerated (quantitative long-day response) by longer photoperiods.
Plants with photoperiodic responses (short-day and long-day plants) are further classified into 2 groups based on the specific response to varied photoperiods: qualitative and quantitative response. Qualitative response in plants happens when a particular photoperiod is an absolute requirement for the occurrence of flowering initiation. In contrast, a quantitative response is when plant flower initiation takes place in both short and long days but one condition accelerates flowering initiation. The degree of quantitative responses is typically cultivar-specific and cultivars with weaker quantitative responses may be mistakenly considered as day-neutral plants.
But, how does photoperiod affect flowering?
Previous research has demonstrated that plants respond to the dark period in each day cycle. For example, Short-day plants will not flower during a short dark period, which is linked to a long day.
Based on the fact that plants respond to dark periods we can then learn that night interruption can break one long night into two short nights. In this case, short nights are related to long-day conditions meaning flowering induction of flowering inhibition (depending on the type of plant) can be controlled by night interruption. Why is this helpful? When trying to promote long-day conditions we usually turn on lights for longer periods. However, by doing night interruption, less electric light is needed. Therefore money can be saved.
Plants of course can have the benefit of longer days which can also promote photosynthesis, growth, and development. But if your intention is only to control the photoperiod, then night interruption can be a good option.
Other important piece of information when looking to induce a photoperiodic response is to learn that plants can have a response to photoperiod from very low light levels (Around 2 μmol m-2 s-1). This is why specific lamps are designed to induce a photoperiodic response. Flowering lamps are usually low intensity. These lamps provide good characteristics in light quantity and quality to induce a photoperiodic response. We also need to learn flowering lamps are not designed to promote strong effects in photosynthesis or growth. They are designed to trigger just a photoperiodic response.
Light quality in flowering induction
Short-day and long-day plants have different photoperiodic response mechanisms, involving components of photo-perception and biological timing. The roles of photoreceptors are essential in the signaling of the photoperiodic control mechanism.
Plant photoreceptors are light-sensitive molecules confirmed by a protein and a light sensible pigment capable of regulating flowering by altering the expression of a key flowering regulator. The main photoreceptors involved in flowering regulation are the red/far-red light receptors, called phytochromes. Phytochromes are proteins responsible for photoperiod sensitivity in plants that utilize a linear tetrapyrrole, bilin chromophore to sense red/far-red light, existing in two inter-convertible forms.
One form of phytochrome is Pr, which is considered the inactive form of phytochrome and has a primary absorption peak at the wavelength of 660 nm (red) and a secondary absorption peak at a wavelength around 380 nm (UV-A). The other form of phytochrome is Pfr, which is considered the active form of phytochrome with an absorption peak at 730 nm far-red wavelengths and a smaller peak at 408 nm blue wavelengths.
Pfr accumulation can inhibit flowering in short-day plants and have the exact opposite effect (Flower induction) in long-day plants. During the dark period Pfr changes to Pr form. This is why long periods of darkness in short-day plants promote flowering. If we do a brief exposure with red light during a dark period, Pr will convert again to Pfr form. This is why night interruption works! In summary, night interruption can be used to avoid flowering in short-day plants or promote flowering in long-day plants.
Research applications
There are other factors affecting flowering response. Some good examples are temperature and Daily Light Integral (DLI). This is why flowering lamps can be really useful for research purposes.
When trying to test photoperiodic treatments and response in plants, it is recommended to extend the period of light artificially under the same temperature and maintain the same DLI within the treatments. In order to maintain the same DLI, the extended period of light should be really low light intensity. By applying treatments correctly we will be able to measure only the effect of photoperiod in flowering response.
Greenhouse application
We can use different lamps in greenhouse operations to promote or inhibit flowering. Regular lamps designed for greenhouse operation to promote higher DLI (e.g. L1000 by Current) can also be used to induce a photoperiodic response. By adding light using regular growing lamps we can increase DLI, which can be good for different crops and also be useful to create longer days when looking to promote flowering in long-day plants or inhibits flowering in short-day plants. If your objective is only to induce a photoperiodic response, then night interruption can be used.
In order to create a short day in a greenhouse, we usually use covers to eliminate natural light, when natural light is above the threshold for a short-day plant. Other options include moving plants or transplants from the greenhouse to a growth chamber in darkness for specific periods of time in order to induce flowering in short-day plants.
There is always an advantage in learning about photoperiod when working with long and short-day plants. Remember the more you know the better you can manage not only your growing system. But also your investment of capital for your projects… and of course! If you need any help in the process Hort Americas will be on board to help you make the best decisions for your projects.
Chris Higgins, CEO, Hort Americas
Plants can be classified based on photoperiodic response in day-neutral, short-day and long-day plants. Day-neutral plants flower at the same time irrespective of the photoperiod. Short-day plants are plants that require a photoperiod shorter than a specific threshold (called ‘critical photoperiod’) to initiate flowers (qualitative short-day response) or plants that flower initiation is accelerated by shorter photoperiods (quantitative short-day response). Long-day plants are plants that require a photoperiod longer than a specific threshold to initiate flowers (qualitative long-day response) or plants that flower initiation is accelerated (quantitative long-day response) by longer photoperiods.
Plants with photoperiodic responses (short-day and long-day plants) are further classified into 2 groups based on the specific response to varied photoperiods: qualitative and quantitative response. Qualitative response in plants happens when a particular photoperiod is an absolute requirement for the occurrence of flowering initiation. In contrast, a quantitative response is when plant flower initiation takes place in both short and long days but one condition accelerates flowering initiation. The degree of quantitative responses is typically cultivar-specific and cultivars with weaker quantitative responses may be mistakenly considered as day-neutral plants.
But, how does photoperiod affect flowering?
Previous research has demonstrated that plants respond to the dark period in each day cycle. For example, Short-day plants will not flower during a short dark period, which is linked to a long day.
Based on the fact that plants respond to dark periods we can then learn that night interruption can break one long night into two short nights. In this case, short nights are related to long-day conditions meaning flowering induction of flowering inhibition (depending on the type of plant) can be controlled by night interruption. Why is this helpful? When trying to promote long-day conditions we usually turn on lights for longer periods. However, by doing night interruption, less electric light is needed. Therefore money can be saved.
Plants of course can have the benefit of longer days which can also promote photosynthesis, growth, and development. But if your intention is only to control the photoperiod, then night interruption can be a good option.
Other important piece of information when looking to induce a photoperiodic response is to learn that plants can have a response to photoperiod from very low light levels (Around 2 μmol m-2 s-1). This is why specific lamps are designed to induce a photoperiodic response. Flowering lamps are usually low intensity. These lamps provide good characteristics in light quantity and quality to induce a photoperiodic response. We also need to learn flowering lamps are not designed to promote strong effects in photosynthesis or growth. They are designed to trigger just a photoperiodic response.
Light quality in flowering induction
Short-day and long-day plants have different photoperiodic response mechanisms, involving components of photo-perception and biological timing. The roles of photoreceptors are essential in the signaling of the photoperiodic control mechanism.
Plant photoreceptors are light-sensitive molecules confirmed by a protein and a light sensible pigment capable of regulating flowering by altering the expression of a key flowering regulator. The main photoreceptors involved in flowering regulation are the red/far-red light receptors, called phytochromes. Phytochromes are proteins responsible for photoperiod sensitivity in plants that utilize a linear tetrapyrrole, bilin chromophore to sense red/far-red light, existing in two inter-convertible forms.
One form of phytochrome is Pr, which is considered the inactive form of phytochrome and has a primary absorption peak at the wavelength of 660 nm (red) and a secondary absorption peak at a wavelength around 380 nm (UV-A). The other form of phytochrome is Pfr, which is considered the active form of phytochrome with an absorption peak at 730 nm far-red wavelengths and a smaller peak at 408 nm blue wavelengths.
Pfr accumulation can inhibit flowering in short-day plants and have the exact opposite effect (Flower induction) in long-day plants. During the dark period Pfr changes to Pr form. This is why long periods of darkness in short-day plants promote flowering. If we do a brief exposure with red light during a dark period, Pr will convert again to Pfr form. This is why night interruption works! In summary, night interruption can be used to avoid flowering in short-day plants or promote flowering in long-day plants.
Research applications
There are other factors affecting flowering response. Some good examples are temperature and Daily Light Integral (DLI). This is why flowering lamps can be really useful for research purposes.
When trying to test photoperiodic treatments and response in plants, it is recommended to extend the period of light artificially under the same temperature and maintain the same DLI within the treatments. In order to maintain the same DLI, the extended period of light should be really low light intensity. By applying treatments correctly we will be able to measure only the effect of photoperiod in flowering response.
Greenhouse application
We can use different lamps in greenhouse operations to promote or inhibit flowering. Regular lamps designed for greenhouse operation to promote higher DLI (e.g. L1000 by Current) can also be used to induce a photoperiodic response. By adding light using regular growing lamps we can increase DLI, which can be good for different crops and also be useful to create longer days when looking to promote flowering in long-day plants or inhibits flowering in short-day plants. If your objective is only to induce a photoperiodic response, then night interruption can be used.
In order to create a short day in a greenhouse, we usually use covers to eliminate natural light, when natural light is above the threshold for a short-day plant. Other options include moving plants or transplants from the greenhouse to a growth chamber in darkness for specific periods of time in order to induce flowering in short-day plants.
There is always an advantage in learning about photoperiod when working with long and short-day plants. Remember the more you know the better you can manage not only your growing system. But also your investment of capital for your projects… and of course! If you need any help in the process Hort Americas will be on board to help you make the best decisions for your projects.
Chris Higgins, CEO, Hort Americas
Current expands horticulture LED portfolio with new integral intra-canopy lighting
Colin Woodford
GE Current, a Daintree company
- As seen in Vertical Farm Daily Publication date: Thu 24 Mar 2022
GE Current, a Daintree company
- As seen in Vertical Farm Daily Publication date: Thu 24 Mar 2022
New Arize Integral intra-canopy lighting (ICL) fixture
GE Current, a Daintree company has added a new category to its Arize range of horticultural LED solutions, with the launch of the Arize Integral intra-canopy lighting (ICL) fixture. Offering best-in-class lighting output of up to 346 µmol/s and efficiency of 3.5 µmol/J, the Integral is designed to help growers maximize yields of high-wire crops such as tomatoes, cucumber, and peppers through the more strategic deployment of light, deep within the plant canopy.
Designed for use in combination with Current’s Arize Element L1000 top light, the Integral disperses a tailored light spectrum across a wide, 120-degree angle from both sides of the fixture, to provide the mature leaves lower in the canopy with higher photosynthetic capacity. This allows the plant to make more effective use of the available light energy to drive plant growth and fruit development, without increasing overall energy usage and associated operational costs.
Designed for use in combination with Current’s Arize Element L1000 top light, the Integral disperses a tailored light spectrum across a wide, 120-degree angle from both sides of the fixture, to provide the mature leaves lower in the canopy with higher photosynthetic capacity. This allows the plant to make more effective use of the available light energy to drive plant growth and fruit development, without increasing overall energy usage and associated operational costs.
A recent study conducted with Wageningen University & Research and using Integral, has revealed a 14% increase in tomato yields, with no impact on quality or taste, when the supplemental light energy was delivered through a 66:34 ratio of top lighting to ICL vs 100% top lighting. Dr. Leo Marcelis, Professor of Horticulture & Product Physiology at Wageningen University & Research commented, “We were expecting higher yields from the 34% ICL treatment but we were shocked by the scale of the increase in output.”
The Arize Integral ICL helped boost tomato yields by 14% in a recent Wageningen University & Research study, using a 66:34 ratio of top light to ICL
Bruno D’Amico, Global Product Manager for Horticulture Lighting at Current said, ”By including an intra-canopy lighting solution within our toolkit, we’re able to offer growers even more flexibility when designing a lighting strategy that will maximize the productivity of every harvest. WUR’s research has clearly shown the value of considering ICL within a greenhouse environment and we’re currently working with a number of growers to demonstrate the impact of the Arize Integral as part of their supplemental lighting plans.”
For added peace of mind, the Integral’s lifespan exceeds 54,000 hours at L90 and is covered by Current’s market-leading, five year warranty.
For added peace of mind, the Integral’s lifespan exceeds 54,000 hours at L90 and is covered by Current’s market-leading, five year warranty.