I have wanted to purchase grow lights and start my seedlings indoors for many years. However, commercial grow lights were cost prohibitive. After a bit of research, we have come up with the perfect inexpensive solution to meet our needs.
What is an inexpensive alternative to expensive standard grow lights? Seedlings can be effectively grown with inexpensive shop lights as long as you purchase the right bulbs. Use a bulb with a Kelvin rating of 5,000 to 6,500, and an output of at least 2,500 lumens.
In this post, we will share how we designed this inexpensive lighting system to start seedlings indoors. It is significantly less expensive than standard grow lights and performs just as well. It may be inexpensive but it isn’t cheap. Our indoor lighting system should last for many years.
A standard shop light fixture is ideal. Select daylight balance in a fluorescent or LED bulb with a Kelvin rating of at least 5,000 and a minimum of 2,500 lumens. Get a fixture that will accommodate 2 to 4 bulbs that can be suspended by a chain and adjusted as the plants grow.
How much does a lighting system cost to start seedlings indoors?
We chose T8 style fixtures and bulbs. Fixtures were about $18 each, and bulbs were about $2.50 each (in the 30 bulb carton).
How much does it cost to operate these grow lights?
The bulbs consume 32 watts each and will last for about 6.5 years if used for 15 hours each day. Operation costs are about 70 cents per 15 hour day for the 12 bulbs (at $0.12/Kwh).
Seedlings can easily be started indoors. A bright sunny window may do the trick, but chances are you will need some kind of florescent or high-density plant light to get good results.
Best Location for Starting Seedlings Indoors
A window with strong sun is an ideal location for providing your plants with adequate light. Some windows have coatings that prevents the sun from damaging furniture and carpets. That same coating limits the effectiveness of the light coming in from that window.
Any spot where you can suspend a shop light above the plants will work to grow plants. Be creative. Find a space in a kitchen, laundry room, bathroom, or even on a shelving unit in the family room.
These photos are from our friend, Kenneth’s home. He has been successfully using this type of lighting system for years.
Air movement helps young seedling grow strong and healthy. Consider potential for gentle air movement when determining your location.
Minimum Bulb Ratings for Grow Lights
Select a bulb with a Kelvin rating of at least 5,000 to 6,500. The higher the kelvin rating the better. The lumen rating should be 2,500 or higher. You can find them on Amazon here or pick them up at your local hardware store.
It is best to use a lighting fixture that will accommodate a minimum of 2 bulbs.
Ideal Distance Between Light and Top of Plant
When lighting is placed too far above the plant, you will get seedlings that are long and leggy. For healthier plants, adjust the light fixture so that it is not too far above the top of the plants. It is really easy to adjust the height if the light suspended by chains.
Minimum Indoor Lighting Time Requirement
Seedlings will thrive with between 12 and 18 hours of light each day. Artificial light is not as intense as summer sun. Plants will need more time under the grow lights to reap the same benefits as they would outside under the sun. Plants need some dark to rest from the hard work of photosynthesis.
The easiest way to regulate the timing of artificial lighting is to use an automatic timer. They are relatively inexpensive and do a great job of simplifying the process.
When should seedlings be moved under grow lights?
Most seedlings will sprout in a warm, dark location. The first two leaves that appear (cotyledons) are food sources for the baby plant until the true leaves form and can begin photosynthesis to feed the plant. Once the true leaves appear it is time to move them under a light source and give them 12-18 hours of light each day.
Moisture Requirements for Indoor Seedlings
Keep the potting soil moist but not wet. Seedlings don’t like soggy feet, yet they need consistent moisture to be healthy. We like to water our seedlings every day with a little squirt bottle. The gentle stream prevents the soil from being disrupted during watering.
Air Movement Requirements for Seedlings
Germination can be enhanced by creating a greenhouse effect. Simply cover newly planted seed trays loosely with plastic wrap. It is important to allow a little bit of air to facilitate plant growth and not mold growth. The plastic wrap should be removed as soon as the seedling immerges from the soil.
New little seedlings should be kept away from drafts. That being said, a gentle breeze will help the seedlings grow strong and healthy.
Soil Requirements for Starting Seedlings
Tiny seedlings can easily be burned by potting soil that contains fertilizers. It is best to start seedlings in a medium that will provide optimal results such as a commercial seedling propagation mix or homemade mixture that contains peat moss or coir, Perlite, garden soil, compost and a little bit of lime.
Tom Bartels recommends adding an organic base fertilizer that contains lime, greensand, phosphate rock, and cottonseed or alfalfa meal. Learn more about Tom’s biointensive organic gardening methods here.
Heat Requirements for Seed Germination
Most seeds do not require light in order to germinate but they do require heat. Lettuce is an example of a seed that requires light for germination to take place. You can safely sprout most plants in the dark.
Place your seedling containers in a warm, draft free location. Optimal germination temperatures are between 60°F and 70°F. The top of a refrigerator may be a good location to facilitate germination for seeds that do not require light to germinate.
Seedling heat mats are designed to be placed underneath seedling trays and gently warm the soil from underneath. They can be beneficial when growing plants with higher temperature requirements, like peppers.
Our grow light set up is in our solarium which is nicely warmed by the sun. We had a high rate of germination without adding additional heat, with the exception of our peppers. They were quite slow to germinate and probably would have been happier with an additional heat source.
We plant more seeds in each container than we intend to keep to account for low germination rates. It is a good idea to take care of the extra seedlings before they get very large. I usually just take a pair of scissors and cut off the weaker seedlings at the base. This helps to avoid damage to the other seedling from pulling the plant out.
It is also possible to separate the seedlings and repot them. I like to take advantage of multiple healthy seedlings and carefully divide them when planting them outside. This only works if the plants have not grown too large and the roots entangled.
One surefire way to kill a seedling is to take it from under the protective environment of the grow lights and plant it outside in a relatively harsh environment. Plants can easily be sunburned by the relentless sun, or can be wind burned and die.
When the weather warms, I take my seedling trays and place them on the back patio for a few hours each day. They get a little bit of morning sun before the patio shades them. I take them back inside at night for the first few days.
Then I transition them to a position where they will get a little bit more sun each day and leave them out overnight as long as the temperature is favorable. This gives them a chance to slowly acclimate to the sunlight, breezes, and temperature changes in the outdoor environment.
In the past, I have lost precious seedlings due to a lack of patience. This is a process that absolutely can’t be skipped or shortened. I usually harden off my plants for at least a week before planting them in full sun.
These inexpensive shop lights, along with the right bulbs, have made starting healthy seedlings inside our home simple and rewarding. Ultimately, we are saving much more money by starting our own seedlings in used containers, than purchasing them from a local nursery.
Another great benefit to starting seedlings indoors is the potential for succession planting. Once a plant is harvested in the garden, we have another seedling ready to take its place. This is a great way to increase production in a small space and take advantage of the entire growing season.
I love being able to select my own plant varieties instead of being dependent upon the choices available at the nursery. These grow lights also help us to be more self-reliant as we save seeds each year and reduce our need to depend on outside sources to feed our family.
One of the great things that we have discovered is that we can use these same grow lights to produce greens for our family year-round. Check out How to Grow Fresh Greens Inside Your Home All Year Long to see exactly how we do that.
Thanks for being part of the solution!
Jonathan and Kylene Jones
