These days, LED grow lights are really popular! Light emitting diodes, or LEDs, are incredibly effective and can be fairly powerful. However, some vintage gardeners insist on using their original fluorescent lighting instead.
The term “fluorescent” refers to a variety of lighting types, including basic fluorescent tubes, high-output T5 fluorescent tubes, compact fluorescent lights (CFLs), and more. T5 fluorescent grow lights are regarded as the ideal option for plants. T8 tubes can be used to light indoor seedlings or lettuce plants adequately even if they are less effective and bright than T12 tubes.
In general, a typical 45 or 60 watt incandescent light bulb (or LED equivalent) used in a home lamp fixture won’t produce enough light to sow seeds or grow other plants that need a lot of light.
Differences between fluorescents and LEDs
- LED lighting often uses less energy than fluorescent lighting, which results in cheaper electricity costs.
- Although they normally cost more up front than traditional fluorescent tube lights, LED lights may last longer.
- LED lights have a larger range of shapes and sizes because they are composed of several diodes. T5 fluorescents are long, thin tubes with one or more tubes fitted in a ballast fixture (such as “shop lights”).
- LED lights produce more lumens of light per watt. So, depending on the specs of each light, a compact LED fixture may be able to produce more light than a comparablely sized T5 fixture. Some LED lights are not as strong as T5s.
- LED grow lights are typically suspended several feet above plants, compared to T5 fluorescent lights, which can only be kept a few inches above plants. Fluorescents are therefore more suitable for shelf systems with small spaces. Read the individual instructions for each light!
You’ll see different ratings for light temperature, Kelvins, watts, lumens, and other factors when you look for grow lights. I’ll do my best to keep it as easy as possible because this subject has the potential to become difficult (and frequently does)!
What color grow light should I get?
Select a grow lamp that is referred to as “full-spectrum or broad spectrum” for indoor seedling growth. The same is what I advise for indoor plants. You receive the most like natural sunshine possible when using a full-spectrum light, which has a healthy combination of blue and red light. That makes logical, no?
Cool blue light is wonderful for developing leafy green foliage but also limits plant growth, keeping plants short and stocky, if you’re really curious to know the difference. Although this is excellent for seedlings and microgreens (or plants in the “veg” stage), too much blue can eventually cause plants to become stunted. Warm red light promotes vegetative development as well as flowering, but too much red light can cause plants to become tall and lean. The majority of the light produced by standard household incandescent light bulbs is warm and inviting but is not good for plants.
Look for the grow light’s Kelvin rating if the temperature isn’t indicated explicitly. That will reveal the hue of the light it will produce. A full-spectrum grow lamp with a Kelvin level of 5000 to 6500K will closely approximate natural daylight. Warm or reddish lamps have even lower ratings, about 3000K, whereas cooler blue grow lights have a rating around 4000K. A “cool white light” (4100-4500K) will also work well for germinating vegetable seedlings, growing microgreens, and rearing young transplants if you can’t find a full-spectrum light in the correct Kelvin range that also matches your other demands (price, size, availability, etc.).
A source’s output of visible light is measured in lumens. The light gets brighter and more powerful the more lumens it has. The minimal amount of light needed per square foot of growing space for vegetable seedlings and other “full sun plants” is between 2000 and 3000 lumens. So utilizing a grow light that emits 3000 lumens is adequate if you’re only growing a single normal tray of seedlings. If not, scale up to a brighter light using math. Alternately, use several light sources to cover a larger area with a strong canopy of light.
Consider a grow area that is 3 feet by 3 feet, or the equivalent of 9 square feet, for illustration. The average of the suitable range multiplied by 9, or 2500 lumens, shows us that a 22,500 lumen light would be suitable (or several lights that add up to cover that space). Don’t worry if math isn’t your strongest subject. The majority of grow light manufacturers list the square footage that each light is intended to cover.
Finally, remember that brightness is not determined by watts! A low wattage LED (let’s say 20 watts) may emit an even brighter, more brilliant light than a 60 watt incandescent or fluorescent bulb because, as we briefly covered earlier, LED lights emit more lumens per watt.
When determining the appropriate size for grow lights, take into account two factors: the size of the light fixture itself and the size of the surface area that the grow light is intended to appropriately illuminate. (Also see the section regarding square footage and lumens above.) The size of light that will work for you directly depends on your growing space, ideal setup, and number of plants.
Are seedlings or trays of microgreens being grown on a shelf? Try hanging LED strips or fluorescent tube lights from the shelf above. Do you have a dark spot in your living room that you’d want to use to keep one or more indoor plants? Use a single powerful LED bulb or a modern lamp fixture that complements your interior design. In a grow tent, beginning seedlings on a table in your garage, or other larger area, panels or boxy light lights are excellent.
Some grow lights cast light over an area that is much larger than the light source itself. Only the plants directly beneath the lights are sufficiently supported by the others. Your plants will tell you if you’re unsure. Around the edges of the light canopy, seedlings frequently tilt inward toward the brighter light. You could then require a larger light. Or, to ensure that every plant has an equal amount of time in the spotlight, you’ll need to regularly rotate the seedling trays that are below the light every day or two.
Also keep in mind that before transferring seedlings from small seed-starting cells to larger containers for outdoor planting, the majority of gardeners pot them up at least once and perhaps twice. The plants will now take up more room beneath a light as a result of the switch to a larger container size. In other words, when you first start out planting seeds, you could need bigger (or more) lights than you think!
How much light should a house plant receive?
Making decisions about lighting arrangements for any indoor garden can be difficult. The horticultural lighting sector occasionally gives off the impression of deliberately trying to perplex us, perhaps in an effort to persuade customers to buy more or more expensive equipment than they actually need.
The fact that many bulbs are still sold using “lumens as a selling factor” is an excellent illustration of this. Lumens are a unit of measurement for the quantity of light, but they should not be used in horticulture.
If you wanted to light a stage or illuminate an object for viewing, you would use lumens to indicate the intensity of the light. However, the proper measurement of light for photosynthetic processes employs PAR values, which stand for “photosynthetically active radiation. This method of measuring light offers data on a source’s output’s quantity and quality in relation to how well and efficiently it supports photosynthesis in plants. It considers spectrum, measured by color or wavelengths, in addition to strength, measured by photon count.
However, since you explicitly ask about lighting a particular amount of space, I won’t go into too much detail on PAR and instead will respond to your question in a simpler manner. Lumens definitely have a role in this discussion. We need to first comprehend the ideal amount of light for plant growth and development using a 4′ x 4′ grow tent as our model for the area we wish to light. To do this, we look at photosynthesis, the mechanism through which light energy (photons) is transformed into plant energy (glucose or sugar).
Between 3,000 and 4,000 lumens per square foot of sunshine is ideal for most plant leaves to convert their energy. Let’s say that a 1,000 watt high-pressure sodium (HPS) bulb produces 100,000 lumens on average. With a leaf’s maximum efficiency of 4,000 lumens per square foot, a 1,000-watt bulb should have an ideal coverage area of 25 square feet, or a 5′ x 5′ footprint.
Of course, salespeople from garden shops and bulb manufacturers will claim that a 1,000-watt bulb covers an area of 6′ x 6′ to 8′ x 8′, but this claim is not based on photosynthetic processes but rather on the amount of physical light it emits (hence the use of lumens and not PAR).
However, even from a more objective standpoint, it seems like a 1,000-watt HPS would be more than enough to illuminate a 4′ by 4′ tent, which is only 16 square feet. But there is still another element that is sometimes overlooked while selecting the right lamp: heat byproduct.
The amount of heat that a 1,000-watt bulb can generate for a garden, especially a compact garden space like a tent, is astounding. In fact, when you dissect and examine photosynthesis even more, you discover that the process also has optimum temperatures. The “gold zone” for photosynthesis is precisely the range from 68 to 74 degrees Fahrenheit. Plant photosynthesis starts to considerably slow down at 84F and above.
Therefore, even though a 1,000 watt bulb may appear to be quite powerful for a 4′ by 4′, it will be excessively bright. A 1,000 watt bulb has the ability to quickly elevate the temperature by over 25 degrees in a 4′ x 4′ x 8′ tent that has no exhaust. In other words, 68F can rise to above 90F! You’d struggle to maintain the temperature below 80F even with a lot of exhaust.
The answer is straightforward: a 400-watt or 600-watt will work much better for you and your plants. 50,000 lumens or so are produced by a 400-watt HPS. 3,125 lumens per square foot are produced with a 16-square-foot footprint in a 4′ x 4′. In the same tent, a 600-watt light source produces around 80,000 lumens, or 5,000 lumens per square foot.
The 400-watt HPS will therefore be the wiser choice in a 4′ x 4′ due mostly to the heat issue, which should never be underestimated. Having said that, you may take into consideration the 600 if you’re crowding more than four plants into a 4′ x 4′ and you intend to have great exhaust and perhaps even some cooler air being pushed into the tent, but it would be hazardous. The 600 can cost you more in terms of quality than you would gain over the 400 in yield if you don’t appropriately mitigate the heat.
Do plants need more light than 200 lumens?
How much light do your plants actually require? It’s quite challenging to provide a response to that issue because so many diverse things are involved. You must take into account the size of your room, the kind of plant you’re growing, and the yield you’re after. There may not be a perfect number, but in general, your plants should do pretty well if you can create between 300 and 800 lumens per square foot.
How much artificial light do plants in containers require?
It can be challenging to provide plants the right amount of light while they are being grown inside in order to keep them happy and healthy. Winter has arrived, which further reduces the quantity of natural sunlight accessible because the days are shorter and the nights are longer. At this time of year, the sun’s strength is also lessened. Artificial lighting should be used to augment or replace natural sunshine in order to cultivate healthy, beautiful houseplants and to maintain the bloom of blooming plants throughout the winter.
The light that a plant is exposed to must closely resemble sunshine for healthy growth. All of the hues in the spectrum are present in sunlight, and each is essential for the process of photosynthesis. Two of the most essential hues for the growth of plants are red and blue. Red encourages vegetative growth and flowering, but too much of it will make a plant lanky and strained. A fuller, stockier plant results from blue’s control of plant growth. Select a full-spectrum fluorescent gro-bulb for the best effects. For the healthiest and most vibrant houseplants, this lighting option is ideal.
Varying plant species require different levels of light. While some plants like dim lighting, others need intense light. The wattage of the lightbulb and the distance between the light source and the plant dictate the amount of light that is produced by artificial lighting. Knowing which plants to gather together beneath the fixture and where to position a light will tremendously aid you when choosing where to do so. Plants produced primarily for their leaves typically need less light than those grown for fruit and flowers, as a general rule of thumb. Plants exposed to artificial light should be rotated every week because the light from tube-style bulbs is stronger in the middle than at the ends. To enhance the quantity of light available to your plants, use white trays, mirrors, or trays lined with foil.
The majority of houseplants thrive with 12–16 hours a day of artificial fluorescent light. A plant will grow tall and spindly if it receives insufficient light, and it will wilt, lose color, have overly dry soil, and burn its leaf if it receives too much light. Each day, plants too need to take a break. Your plants’ development rate will be slowed down by an 8–12 hour period of darkness each day, which will also provide them the rest they need to form flower buds. For instance, the Christmas cactus requires six weeks of uninterrupted darkness—13 hours each day—to set bloom buds. The Christmas cactus won’t flower if it doesn’t get the necessary amount of downtime. To control the length of time your indoor plants are exposed to light and darkness, use an automatic timer.
The ability of the fixture to be adjusted is crucial when picking a plant light fixture. The fixture should be movable up and down to accommodate the various plant species’ differing needs for light intensity and growth height. You will be limited in the kinds of plants you can grow and how much you can use the fixture if it is not adjustable. Both adjustable shop lights and tabletop light fixtures are suitable for illuminating indoor plants. The size of the fixture is another factor. The amount of plants you intend to grow below the light should guide your size selection. Plants can be grown on multiple levels of lighting shelves that are provided by illuminated plant carts. While tabletop fixtures are lightweight and may be moved to new locations when needed, carts have wheels that make them portable.
Starting to use artificial light sources may seem scary, but you’ll be astonished at the impact it will make to all of your indoor plants, both houseplants and seedlings.