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Seed Starting 101: The Needs of Seeds

May 14th, 2010

The most important thing to pay attention to when you’re starting seeds is the needs of each type of seed. Not all seeds are created equal. Some need light to germinate, others need darkness. Some seeds need warm soil, others need cool soil. Some seeds need a cold spell before being able to germinate, others need some heat. Some seeds do better if they’re scarified, which is the scratching, breaking or softening the tough seed coat. You need to research and figure out the needs of the types of seeds you’re trying to start or you will be disappointed with low or no germination.

Plants are like anything else so the #1 rule for seed starting is to: READ THE INSTRUCTIONS BEFORE PLANTING. There’s nothing more frustrating than seeding a tray of alyssum and then remembering that they need light to germinate, and of course you covered them with soil. Most plant packets contain all the information you need, with planting depths, light requirement, stratification or any other special needs. If you bought heirloom seeds, or traded seeds with someone, Google will provide you with a wealth of information about that specific type of seed. This is the best way to ensure proper germination and a happy gardener!

The second most important thing when it comes to good germination is to MAKE SURE YOUR SEEDS ARE FRESH. Since seeds are a living thing, although dormant until given the right conditions, they need to be treated with care and they have a shelf life. Different kinds of seeds have different shelf lives, some last for years and years others for only a year or less. If you save seeds past their normal shelf lives you risk low or no germination, which is frustrating! If seeds are stored properly their shelf life will be normal and if stored in the fridge or freezer you can save them 2-5. I wrote a post about the shelf life of seeds already, you can download this chart from my Flickr account if you’d like a copy.

You’ll also need to DETERMINE IF YOUR SEEDS NEED LIGHT TO GERMINATE. Some seeds need light, others need darkness, some don’t care either way. Hollyhocks need light to germinate, that’s why I floated them in water in my kitchen windowsill. It seems that the smaller seeds need light for germination, so they need to be sown on top of the soil. Tomatoes, peppers and other vegetables don’t really care, these seeds are covered with soil when planting (1-1.5 times as deep as the seed).

FIND OUT IF YOUR SEEDS NEED WARM OR COOL SOIL. Some seeds need warmth to germinate, like tomatoes and peppers. Others prefer cooler soil, like spinach and lettuce. Often the conditions the seeds prefer are just like the conditions the adult plants like, which is nice because it makes it pretty easy to know. When I’m planting cool vegetables I often sow seeds in the flats and put them on the floor of the basement, which keeps the soil about 55 degrees. This is perfect for lettuce and spinach. If I’m seeding warm soil vegetables, I put the flats on a seedling heat mat or in a warm spot, like the top of the fridge. I’ll often put these trays outside on warm sunny spring day, this warms the soil better than anything, especially when using the dark plastic trays with a clear dome. Of course they’ll need carried back indoors when the temperature drops at night. Here’s a great chart that lists different vegetables and the germination rates depending on the soil temperatures. With a little searching on-line you should be able to find specific information for each kind of vegetable. And don’t be afraid to experiment, seeds are cheap. Seed two flats and try putting one outside and one in the house, after a few years you’ll learn what methods work best for what you’re growing.

You’ll need to DETERMINE IF YOUR SEEDS NEED A COLD SPELL TO GERMINATE. If your just starting vegetable seeds you probably won’t have to worry about this. You’ll need to learn once you graduate on to other seeds, especially fruits, and wild plants, they often require a certain length of cold before they will germinate. You will need to mimic the natural conditions for these seeds. It’s not difficult, all you need to do is plant the seeds in a tray, water and put the tray outside in January or February (if you live in a cold climate) and they’ll germinate when the weather is right in the spring. You can also put the in the fridge, but I never have room and the porch is much easier! It’s easiest to germinate these types seeds in their final planting place, especially plants like joe-pye weed and milkweed. Simply gather wild seeds and sprinkle them in your garden in the fall where you’d like them to grow. I’d recommend lightly covering with soil and marking them so you know where you planted them. It would tragic to pull all the seedlings in spring when weeding, then realize they were the seedlings you planted 5 months ago!

SOME SEEDS DO BETTER IF THEY’RE SCARIFIED, which helps the seed break through it’s hard outer coat. Some common vegetables like squashes germinate better if their seeds are scratched or nicked before planting. Others prefer to be soaked for a few hours to soften the hard seed coating, like nasturtium and peas. Some seeds also prefer to travel through the digestive system of a bird or animal before germination, like strawberries, blackberries and other fruits. I don’t always scarify seeds, but I like to ensure the best possible germination so I usually try to remember. With squash seeds I usually rub them on an emery board lightly on the flat side and the edges, and I soak peas, beets, and nasturtiums for a few hours before planting. Scarification isn’t always necessary as a cold spell is for some plants, but you’ll have better germination if you do it.

Lucky for us edible gardeners, most vegetable seeds are ready to germinate. All they need is water and warmth and they’ll spring forth with their tiny green shoots ready to propagate their kind. Once you have great germination rates with vegetables, try moving on do seeds that need stratification and try your hand at those. I enjoy starting vegetables that are easy, but I also enjoy the challenge of starting other more difficult things from seed, like ladies mantle, joe pye weed and soapwort.

Any great tips on the needs of seeds? Have you ever had to stratify, scarify or do anything special for seeds?

The rest of the Seed Starting 101 Series
Why Start from Seed
Getting Started
Soil Mix
The Needs of Seeds
My Workflow
Diseases and Problems
Hardening Off
Learn More Each Season

Visit my Amazon store to see what seed starting supplies I like.

5 Comments to “Seed Starting 101: The Needs of Seeds”
  1. MAYBELLINE on May 14, 2010 at 10:30 am

    I score and soak sweet pea seeds just because that’s the way my dad always did it.

    Seriously, you need to make a Chiot’s almanac. The photos are beautiful and helpful and your method of writing is exactly what works in my brain.

    .-= MAYBELLINE´s last blog ..Tomatoes Are In! =-.

    Reply to MAYBELLINE's comment

  2. warren on May 14, 2010 at 11:33 am

    You have to talk to your seeds and esp your seedlings….just sayin’
    .-= warren´s last blog ..It was raining…in my house =-.

    Reply to warren's comment

    • Susy on May 14, 2010 at 11:08 pm

      Of course!

      Reply to Susy's comment


This is a daily journal of my efforts to cultivate a more simple life, through local eating, gardening and so many other things. We used to live in a small suburban neighborhood Ohio but moved to 153 acres in Liberty, Maine in 2012.

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