Can seeds germinate without light
Why do some seeds germinate only in the dark?
It may be easier to answer the question “Why are some seeds inhibited from germination when in the light”.
The key to this phenomenon is Phytochrome and you need to research that pigment and its different forms to write a full explanation. You will also need to find out about RED and FAR-RED light.
Phytochrome is present in one form in white/sun light and present in a different form after a period in the dark. Normally, the light form decays to the dark form after a few HOURS, but it is converted back again after a few MINUTES in the light. So, a seed on the soil surface gets enough light to keep the dark form of phytochrome low for sufficient time to prevent germination initiation. It is only when the seed is in permanent darkness that the dark form of phytochrome is active for long enough to trigger germination.
Obviously, this prevents such seeds germinating until they are buried.
This mechanism is even more interesting . some seeds will ONLY germinate in the light (I know these are NOT the seeds you asked about), but if the light has first passed through leaves, then germination is inhibited. This enables such seeds to germinate as soon as they receive direct sunlight, but to remain dormant whilst they are under other plants which would give a developing seeding too much competition. It turns out that the spectral quality of light that has passed through leaves is such that it converts the phytochrome to the ‘dark’ form (as I have called it) – even though the seed is on the surface of the soil.
I hope you will find this a fascinating area to research.
Why do some seeds germinate only in the dark?
How to Grow Seeds Indoors Without Lights or Heat Pads
Whether it’s your first time or your 101st time, there’s something about growing seeds indoors that can evoke a childlike sense of wonder and joy in even the most passive personality. These are heady emotions, so you don’t want to let a little thing like starting seeds without a heat mat or light diminish your enthusiasm in any way. Instead, you’ll simply have to be extra vigilant about caring for your seedlings until you’re ready to plant them outdoors. It can be done, and you can do it if you’re willing to cast additional light on your planting repertoire.
Choose Your Seeds Carefully
You may be growing seeds indoors to get a jump on the growing season, to compound your fruit and vegetable harvest or both. Without the benefit of a heating pad for germinating seeds or a plant light, you must be extra choosy about the types of fruit and vegetable seeds you start indoors. The truth is that some plants would give you a hard time anyway, meaning that they would grow better if the seeds were planted directly into the ground without the risk of disturbing the roots.
Root vegetables like beets and carrots are notoriously fussy, so The Old Farmer’s Almanac recommends planting these other fruit and vegetable seeds indoors instead:
- Brussels sprouts
- Swiss chard
Even if you were going full tilt with a heat mat or light, it would be a good idea to anticipate a few losses. So, plant a few more seeds than you had originally planned.
Compensate for a Heat Mat for Seedlings
As you may know, growing seeds indoors occurs in two phases: germinating, when the seedling literally “pops” from the seed, and growing. During the first phase, your seeds will need warmth more than light. To compensate for the lack of a heat mat for your seedlings, plan to put your seedling tray in a room where the temperature ranges between 65 and 75 degrees Fahrenheit. Then, set the tray in a place that provides consistent and gentle warmth, such as the top of a refrigerator or portable freezer (as long as it’s stable).
After leaves begin to sprout from the seed and they grow to about half an inch tall, they will need more light. Without it, they should grow, but they will be thin and gangly. To fortify your seedlings in this phase, place the tray on a sunny, south-facing windowsill, says Burpee. Just remember to rotate the tray every day or so. A plant that is arching toward the sun is a good sign that it’s time to turn the tray in the opposite direction.
It may also help to remember that as much as you think you’re working at a disadvantage without a light or heat mat for your seedlings, overwatering is actually the No. 1 reason that seedlings fail to grow.
Sow Your Seeds
As a rule of thumb, most seeds should be sown indoors about six weeks before the last frost in your area. Gather your seedling tray, peat pots or even an egg carton and follow these planting tips from Family Handyman. First, fill each opening with all-purpose potting mix. One made specifically for seeds is ideal since it is lighter than regular potting soil and is easier for seeds to push through. Make a shallow depression in the soil with your fingertips or the eraser at the end of a pencil.
Sprinkle a few seeds at the depth recommended on the seed packet and then cover the seeds with more soil. Water until the soil is thoroughly moist and then cover the tray with clear plastic wrap to trap the moisture inside. Place the tray in the warm spot you’ve selected. Apply a liquid fertilizer once a week to fortify the seedlings. Once the seedlings emerge, you can remove the plastic wrap for good.
If you’re growing a variety of fruit and vegetable seedlings, keep in mind that they won’t mature at the same pace. Some will grow quickly, while others will play catch-up, mimicking another childlike phenomenon that makes gardening so rewarding.
How to Grow Seeds Indoors Without Lights or Heat Pads. Starting seeds indoors gives you a jump start on the growing season. Better still, seed propagation isn’t overly time-consuming or expensive. You don’t need fancy heating pads or grow lights for success. All you need is sunlight and a room that has a stable, …