We often get beginning growers in the store looking for seed starting advice. To germinate seeds, or take them from dormancy to sprouting, you need to set up the environmental triggers to assist the seed. There are many different techniques for germinating seeds, and a lot of products and advice out there for how to get started if you’ve never done it. So much advice, that it can be very confusing. The following is a little advice for what we have found that works for a wide variety of seeds for flowers, vegetables, herbs, and even cuttings/clones:
When is the best time to start your seeds? If you are going to be growing your plants indoors, then anytime you’re ready is the best time. If you will be transplanting to an outdoor space, then it depends on the weather where you live. Check with The Farmer’s Almanac, or the back of the seed package will usually tell you how many weeks before the expected last frost date for your area to plant. Don’t know the last frost date for your region? This is a good page to help you figure that out.
Getting Your Seeds Planted
Always wear a mask when working with perlite! Perlite is a form of obsidian characterized by spherlulites formed by cracking of the volcanic glass during cooling, used as insulation or in plant growth media. It is like tiny shards of glass and is very dangerous to your lungs if it’s inhaled.
Step one: Coco coir comes in a dehydrated brick. I hydrate the coir according to the package directions. Before doing this you would benefit from reading the notes in the Watering section of this post.
Step two: I mix perlite into the coir at a ratio of one-part perlite to two parts coir. The coir in our mixture holds moisture without staying too wet. The perlite helps aerate and loosen the media for water to drain easily while also retaining moisture. To keep the dust down, we recommend using water from a spray bottle to wet the perlite prior to handling. I stress again to wear your dust mask when handling perlite.
Step three: I have found that using a product with mycorrhizae increases germination rate and root growth rate after the seed sprouts. I mix the package-recommended amount on whichever product I am currently using.
Step four: Fill the seed tray with media and plant your seeds! Tip: A general rule for seeds is to plant them no deeper than one to two times the diameter of the seed. For very tiny seeds (i.e. lettuce) I simply drop a few seeds on the surface of the media and leave them uncovered.
Seeds respond to warmth and need heat to germinate. If your media, or the water you’re using, is too cold, the seeds will stay in their dormant state. Most cool weather plants or plants that do best in spring and autumn (i.e. spinach, kale, etc.) generally need temperatures between 45°F and 70°F to germinate. Seeds that require warmer weather (i.e. tomatoes and zucchini) will germinate better generally between 65°F and 90°F. Most seeds have about a 25-degree range in which germination will be activated in the seed. This is great for us beginners trying out lots of plants for the yard. If your room is cool, and you’re trying to germinate seeds, pick up an agriculture heat mat and thermostat from your local hydroponics store to dial in the ideal temperature.
The light requirement of seeds is a tricky subject. Some seeds do not require light to germinate (mushrooms), some do. There is a ton of scientific research available about this if you’re interested in learning about the phytochrome system in seeds. If you would rather just grow the plant what do you do? My advice: Use a light. Here’s why: All sprouts need light. As soon as that sprout emerges from the media it needs light; even if it didn’t need light to germinate. A seed that needs darkness, planted at the right depth, will be far enough under your media and will be shaded from the light for germination. In the store, we use a Lush Lighting Herbal Vador LED grow light hung beneath a shelf. Others have used CFL’s which are widely available (we also have CFL’s available in the store). Some others have had great success placing their seed tray in front of a south-facing window.
A few notes about water:
- Seeds like to be kept moist, and they don’t like to be immersed in water for too long. If seeds stay too wet for too long they will rot. If seeds stay too dry for too long they will dry out and die.
- Doing a pH test on your water is a really good idea. When water pH is too high or too low, your seeds will not germinate. Most seeds germinate between pH levels 5.8 and 7.0. Matt Johnson wrote an excellent explanation of the importance of checking water pH.
- Water quality can make a big difference in your success rate. If you live with city water consider using RO filtered, or bottled distilled water (READ LABELS! You might be really surprised at some of the stuff that is in bottled water being sold on store shelves!). City water has been treated with all kinds of chemicals to remove bacteria and the like. Some of those chemicals (i.e. chlorine) are not good for plants.
- Water temperature matters. Cold water from a tap is often too cold for germination. Use water within the best temperature range for your plants. Leaving your water to sit out overnight to come to room temperature before you water your seeds is a good idea (Matt Johnson’s article –mentioned above—can give you more good reasons). The water we use to water all the plants here at the store has come to room temperature before it goes on the plants, including the seeds.
How often do we water? Water as often as it takes to keep the media moist and not drenched. We use a variety of techniques to keep our seeds happy: a mister, bottom-watering container, and/or a humidity dome.
The mister has a gentle mist that does not “skate” the tiny seeds (like lettuce) across the top of the media. It’s very important to make sure your seeds stay where you initially place them.
Another watering technique we use is bottom-watering. Put about ¼” of water in the bottom tray for your media to wick up. This technique is very helpful if your media is drying out too fast. If your growing room is dry, bottom-watering combined with a humidity dome may be a good option for you. If you need to step away from watering for a few days, it will retain the moisture for the seeds and keep any small sprouts from drying out. Small plants generally do well with a humidity level around 60%.
How Long Will It Take before I see something happening?
A common question with an answer most of us don’t want to hear… it depends. I will say, the highest success rates come from recreating each particular seed’s ideal germination environment. Most seed packages will give you a time range anywhere from a few days to a few weeks. All seeds are a little different, even the same packet of seeds can have some that sprout quicker than others. Be patient, monitor your temperature and moisture and then you will be rewarded greatly when those first seeds germinate and those little sprouts emerge. It’s exciting to watch those small seeds become large plants. Happy Gardening!