How Many Kelvin Should A Bulb Have In The Vegetative Period?

Last Updated on October 30, 2022 by Cinthia

You’ve probably heard of spectrum light and how it plays a key role in the stages of your plant growth. If you’re a newbie or a little experience and you are wondering how many Kelvin a bulb should have in the vegetative period, you’ve come to the right place.

We will enlighten you on how to go for the accurate light spectrum, color temperature, and many more. So, read on to gain some knowledge.

Plants are generally required to grow under sunlight and for indoor gardens, we make use of grow light. Some grow lights such as fluorescent bulbs have various colors of light required for various stages of the plant life cycle.

Before we dive into how many Kelvin a bulb should have in the vegetative period, let’s have a brief introduction to various colors of light.

How Many T5 Lights Do I Need For Veg
How Many T5 Lights Do I Need For Veg
Brief Introduction to Kelvin’s Light colors

One of the plant’s basic needs is light, be it sunlight, grow light, or other types of light that can mimic sunlight. It is essential to supply your indoor plants with the correct light spectrum at their various stages (such as the vegetative period) for optimal growth.

It may seem reasonable to think because the sun supplies white light in full-spectrum, our grow light should be white. This is not true. Sunlight produces different colors of light and the plant receives all these colors.

Therefore, grow light should have these various colors of light. Plants, however, perform well with red and blue light with a little bit of green and yellow. Because sunlight and other forms of light generally consist of various colors. A simple illustration of the light appearance is through color temperature and it can be delivered or provided by light bulbs.

Durolux t5 Ho Grow Light

The measurement of the bulb color temperature in a source of light is measured in Kelvin (K) on a scale of 1,000 to 10,000.

As an indoor gardener, you should be familiar with the various color temperatures of bulbs for your plant growth. From the Kelvin scale, the lower end scale has the soft hues of the red spectrum or cool white. On the other hand of the Kelvin end scale, we have the blue light spectrum otherwise known as warm white.

The red spectrum of light is required for the flowering and fruiting period in a plant cycle. It is the blue spectrum of the opposite end Kelvin scale, which is the daylight hue that is required for the vegetative period.

How Many Kelvin A Bulb Should Have During The Vegetative Period

Now let’s get to know how many Kelvin a bulb should have in the vegetative period. The vegetative stage of a plant is between seed germination and flowering stage of plant development.

How much light in Vegetative Period

So, the number of Kelvin a bulb should have in the vegetative period should range from 5,000 to 7,500 Kelvin. They make use of the blue light which is at the extreme of the Kelvin scale which is the daylight hue. It is the daylight hours plants go through their vegetative period.

Grow Light Bulb

We can refer to grow light bulbs as multitasking light bulbs. They mimic the effect of sunlight function on the various stages of your plants’ cycle.

T5 and T8 LED tubes are the most customary type of grow light bulbs used in an indoor garden. The Kelvin range of this bulb usually comes in 6,500 Kelvin more or lesser. So this is the color daylight temperature required by plants especially during their vegetative period.

There are other types of excellent grow lights also. Another light bulb-like LED light is obtainable in 4,100 and 10,000 Kelvin. Note that bulb that supplies light of 4,100 Kelvin is known as neutral looking light. They really don’t do much work with plants that are undergoing vegetative stages.


Is 4000K good for veg?

4000K bulb is that better for plants. It's the most common type of light used in greenhouses.

How many Kelvin does a plant need?

I believe it's the same as in your home, or at least in mine. There are different theories of how much heat is needed to grow a plant. 

The "Kelvin" theory says that each individual plant needs a different amount of heat. It's been estimated that a plant needs between 4 and 20°C above its ideal growth temperature to grow normally. But this is only an estimate. That's because the plant will adjust its rate of growth to match the temperature. The "Thermal Time" theory says that plants need to absorb enough heat to bring them up to the right temperature, then stay there for the time it takes to complete one cycle of growth and then go back down again. So they need more than one degree of heat to do that. The "Time and Temperature" theory says that you don't need to give your plant any more than the time it takes to complete one cycle of growth and then go back down again. This means that the amount of heat is less than the time and temperature theory

What color temperature is best for vegetative growth?

The best color temperature range from 5000K to 7000K.

What is vegetative growth?

Plants grow in two ways: by means of a shoot and by means of a root. A plant's shoot, or stem, is the part of the plant that grows above ground. The shoot is used to produce leaves, flowers, fruits, and roots. A plant's root is the part of the plant that grows underground. The root is used to take up water, nutrients, and minerals from the soil. All plants grow by means of photosynthesis. Photosynthesis is the process by which plants use sunlight to make food. The process takes place in leaves, and it is carried out by chlorophyll molecules. During photosynthesis, carbon dioxide (CO2. from the air and water from the soil combine to form glucose, which is stored in the cells of the plant.

Plants use sunlight to make food out of carbon dioxide and water. Plants grow vegetatively to increase their size and to provide more food for themselves. Vegetative growth also allows plants to grow taller.

What stimulates vegetative growth?

As with other organisms, plants grow in response to a combination of internal and external factors. Internal factors include: temperature, moisture, light, nutrients, hormones, and growth regulators (e.g., phytohormones). External factors include: nutrients, light, water, soil pH, and microbes. The plant hormone auxin is responsible for initiating the vegetative phase of growth in many plants. Auxin also regulates other hormones involved in growth. Nutrients Plants need both carbon (C) and nitrogen (N) to grow. When soil is depleted of these nutrients, the plant will stop growing until more C and N are available. The root system absorbs C and N from the soil, so as long as the roots are healthy, the plant should be able to grow. Some plants have special mechanisms for extracting nutrients from the soil. For example, peas and lentils store nutrients in their seeds, which are then released to the soil when the seed germinates. The amount of C and N needed by a plant depends on the species and variety. In general, most plants require 1-2% N and 1-2% C. However, some plants such as tomatoes, peppers, and eggplants require more N than C. Light Light is necessary for photosynthesis. Plants use light energy to convert water and carbon dioxide into sugars.

Light Spectrum For Vegetative Growth

It’s important you get the right color of light for every stage of your plant cycle to grow adequately. The journey of the plant growth and maturity from their seedlings, to adult, flowering, and now fruiting requires different colors of the light spectrum for their growth cycle.

We have concluded that the number of Kelvin a bulb should have in its vegetative period is from 5,000 Kelvin to 7,500 Kelvin. This is the blue spectrum on the Kelvin scale which is the daylight hue. Also, for the flowering and fruiting stage in a plant cycle, the red spectrum is required.