Many growers who are switching from HID to LED think it’s just a matter of taking out the HID system and replacing it with LED. Those growers soon find lower yields or damaged plants and blame the lighting. So how are some growers experiencing good results with LED? Because they took steps to rebalance their grow environment.
Here are items you should consider:
- Heat – One of the advantages of LED is the lower heat produced in your grow room from lighting; however, plants need heat to carry out many processes. Using LED can lower leaf temperature leading to reduced leaf efficiency. So, in some grow rooms, heat will need to be added.
- Environment – While heat is a big factor to the grow environment, so is carbon dioxide (CO2). Adding or removing CO2 from the environment will affect the amount of heat needed to balance the room. Temperature variances will also lead to humidity variances. The higher the temperature, the more water the air can hold. Lower grow room temperatures will lead to higher relative humidity, which in turn affects how the plants respond.
- Watering – As the environment changes in your grow room, so does the amount of water your plants need. The lack of heat leads to reduced leaf transpiration. Growers face the hazard of over-watering if they have not made sufficient adjustments.
- Nutrients – The absorption rates of nutrients may be affected by the grow environment changes. Depending on the LED spectrum, growers may need to make adjustments for the different chemical absorption rates, especially calcium and magnesium.
- Intensity – Many growers assume that since there is so much less heat from an LED, they can hang the light closer to the plants. While this is true, it can lead to serious plant damage if hung too close.
- Spectrum – HID technology tends to be growth-stage specific, though some products, such as CMH, have been shown to be effective for start-to-finish growth. Most LED systems have a broad spectrum and can be used for the entire growth cycle, but lack energy beyond PAR. When choosing any grow light system, it is important to focus on the growth stage you are after and find a spectrum that will provide the right output for your desired results.
Additionally, hanging an LED system closer to the plant canopy will affect how well each LED chip will mix with the others. If the light coming from the chips are not mixed correctly, the intended spectrum will not be reaching the plants. This may cause an uneven canopy and spotty growth.