I returned from a trip abroad last week and checked on the seeds I had started before I went away. Some seedlings struggled in my absence more than others, and it gave me a few ideas for seed starting tips that I wanted to share with you. On this episode, I’ll be supplementing last week’s encore on preparing for seed starting season with more important things to know.
Being away was a good reminder that seed starting is all about the details. Lighting, water, containers and seed quality all play a part in whether your seed starting will be successful.
I have many seed starting seasons under my belt and have honed my technique over the years to yield the best results.
Before proceeding, I want to invite you to my free webinar: “Seed Basics & Beyond: 9 Things to Know Before You Start Plants From Seed.” You can join me on Thursday, January 29th, at noon to learn what seeds need to perform their best. I’ll also tell you more about my comprehensive online course Master Seed Starting, which opened for enrollment on Wednesday. You can register here at a discounted rate through February 2 and receive lifetime access.
Buy Seeds Early and From Trusted Sources
Seed companies can’t grow everything they offer for sale, so they partner with their fellow growers. Even large seed companies rely on wholesalers for some of their stock. If the wholesalers run out of stock of something hard to find, the seed seller you depend on won’t be able to supply that variety.
In December, I planned to make a seed order from one of the seed vendors that I have trusted and used for years. I was trying to be proactive by ordering seeds in advance, but some of the varieties I was looking for were already out of stock. I checked with other companies that I have a history with, and I didn’t have any luck. I had to go to companies I have never used before.
One seed variety was only available from one vendor, and it was a company I had never heard of. I took a chance because I really wanted those seeds. But when the seeds came in the mail, there was no sell-by date or use-by date on the package. There was no indication of the viability or the freshness of the seeds. That was a red flag for me.
Some seeds never germinated, and those that did faded away quickly. They were just not good quality seeds.
Do your best to order in advance and from companies with a good reputation so you can be assured that you are getting fresh seed.
I found some tomato seed varieties I needed on eBay and Etsy. These individuals or mom-and-pop online businesses don’t always have protocols in place to ensure that seed varieties aren’t mixed up. The seed arrived and did appear to be as advertised, though I had to take it on good faith that the seeds were fresh.
If you wait to order seeds from trusted companies, you may find that the seeds you want are sold out. You can turn to unknown companies, but those less reputable sellers won’t offer the same quality and pease of mind.
Save by Ordering in Bulk
Maybe 25 seeds in a packet of tomato seeds is plenty for you, not only for one season, but for multiple seasons. But if you use a lot of seeds each year, consider buying larger packets.
I have found that oftentimes two of the smallest packets will cost more than a single packet of the next size up. And the next size up has far more seeds than the combined total of the two individual packets.
My daughter Amy and I have a seedling sale every year, so when I buy seeds of a certain tomato variety, I need far more than 25 seeds. Instead of buying multiple 25-seed packets, I buy one ounce of seeds. An ounce, depending on the type of seed you are buying, may mean a few hundred or even a few thousand seeds.
If I end up with way more seeds than I am going to need this season and maybe even the next, it’s still a good deal. I know that I can store my seeds well for good longevity and use them for years to come.
If you only new a few seeds of a certain variety for your garden, one packet will do. But if you require a greater number of seeds than fits in one consumer-size packet, you can save money by purchasing seeds by the ounce.
Don’t Scorch Plants with Hot Lights
I use both fluorescent grow lights and LED grow lights. One downside of fluorescent lights is they put off heat, which may not be a problem in an unheated greenhouse but can be a concern indoors.
Keep the tops of the plants away from the bulbs to avoid scorching plants with hot lights. You need to pay attention to that on a daily basis.
It’s important to maintain moisture in seed trays. Between heat from overhead lights and heat from germination mats, seed starting mix can dry out quickly and the plants can get fried. You should check your seedlings every day, raise the lights higher when necessary and ensure there is enough water in the tray.
If a light source is overheating seedlings, move the light higher to avoid scorching the plants.
Save Money and Reduce Waste With Soil Blocks and Reusable Seed Trays
I don’t buy single-use plastic cell trays. They are such a waste. I use soil blocks and reusable cell trays.
Several years ago I found Winstrip trays from Neversink Farm. I have great success using those. You can drive a truck over them — they’re going to last forever. I really like that, and I also like that the way they’re designed, with slits around all the sides of the cells, they allow greater airflow for improved root development.
Using Winstrip trays simulates soil blocking because when the roots hit the air, they stop growing in that direction.
Winstrip trays are easy to work with and allow you to get seeds sown quickly. Just fill a tray with your soil mix and drop those seeds in, water them, put the lid on and you’re good to go.
Alternatively, you can use soil blocks. There’s no plastic involved. A soil blocker tool shapes and compresses the soil mix into a cube. You eject the cube from the metal mold and you’ve got your little blocks of soil. Just add your seeds on top.
Soil blocks make transplanting very easy, with no transplant shock. All you’re really doing is picking up the block and dropping it into the bump-up container, back filling it, and you’re done.
When using traditional plastic trays, ejecting the seedlings and soil from the trays can cause root disturbance that is rarely fatal but does set the plants back a bit.
Soil blocking takes some practice to get the hang of before the soil mix needs to be the right consistency in order for it to hold together. You’ll start with a container of soil and add water until the mix has the consistency of brownie mix.
You’ll have to experiment with that until you get a sense of how much is enough water. You need enough, but not too much. But it’s better to err on more than less.
So soil blocking takes longer on the front end, but you save time on the back end.
Soil blocks tend to dry out quicker because they’re exposed on all sides. So if you’ve got a fluorescent grow light over the top, it’s probably going to dry the block out faster unless you keep up with the watering. When sowing in plastic cell trays, the soil is more protected around the side, so it is not as likely to dry out as quickly.
A soil blocker tool shapes and compresses the soil mix into a cube. You eject the cube from the metal mold and you’ve got your little blocks of soil. Just add your seeds on top.
What to Know About Seed Starting Discs
If you’re buying seed starting supplies at the box store, oftentimes you’ll see those kits that have the single-use plastic cell tray, the plastic top, and then little round discs of compressed peat moss. When you add water, the discs expand, and you add your seeds to the tops.
Plastic mesh holds the peat moss in place. Even though it’s advertised that you can just drop those into the ground when you’re ready to plant, that mesh doesn’t break down for a long time.
However, you can tear the mesh away before transplanting. The peat moss block will be held together by the roots at this point.
Other plastic-free methods include using paper pots made with newspaper or the seed snail technique.
I hope you learned something to make your seed starting experience more successful. If you haven’t listened to the podcast yet, you can do so now by scrolling to the top of the page and clicking the Play icon in the green bar under the page title.
What do you sow your seeds in, and what has worked best for you?? Let us know what you learned in the comments below.
Links & Resources
Some product links in this guide are affiliate links. See full disclosure below.
Episode 083: Gardening Indoors: The Science of Light, with Leslie Halleck
Episode 187: The Informed Seed Shopper: What to Know Before You Buy
Episode 297: Seed Starting Essentials
Episode 399: Preparation and Seed Organization Tips for a Stress-Free Seed Starting Season
joegardener blog: The Best Soil Temperature for Seed Germination
joegardener Online Gardening Academy™: Popular courses on gardening fundamentals; managing pests, diseases & weeds; seed starting and more.
joegardener Online Gardening Academy Organic Vegetable Gardening: My new premium online course. The course is designed to be a comprehensive guide to starting, growing, nurturing and harvesting your favorite vegetables, no matter what you love to eat, no matter where you live, no matter your level of gardening experience.
joegardener Online Gardening Academy Master Seed Starting: Everything you need to know to start your own plants from seed — indoors and out.
joegardener Online Gardening Academy Beginning Gardener Fundamentals: Essential principles to know to create a thriving garden.
joegardener Online Gardening Academy Growing Epic Tomatoes: Learn how to grow epic tomatoes with Joe Lamp’l and Craig LeHoullier.
joegardener Online Gardening Academy Master Pests, Diseases & Weeds: Learn the proactive steps to take to manage pests, diseases and weeds for a more successful garden with a lot less frustration. Just $47 for lifetime access!
joegardener Online Gardening Academy Perfect Soil Recipe Master Class: Learn how to create the perfect soil environment for thriving plants.
Winstrip trays from Neversink Farm
Soil3 – Our podcast episode sponsor and Brand Partner of joegardener.com – Enter code JoeGardener26 for $5 off
Disclosure: As an Amazon Associate, I earn from qualifying purchases. I receive a commission every time you purchase a product through an Amazon affiliate link. Some product links in this guide are affiliate links. However, none of the prices of these resources have been increased to compensate us, and compensation is not an influencing factor on their inclusion here. The selection of all items featured in this post and podcast was based solely on merit and in no way influenced by any affiliate or financial incentive, or contractual relationship. At the time of this writing, Joe Lamp’l has professional relationships with the following companies who may have products included in this post and podcast: Milorganite, Soil3, Territorial Seed Company, Cool Springs Press / Quarto Group and Dramm. These companies are either Brand Partners of joegardener.com and/or advertise on our website. However, we receive no additional compensation from the sales or promotion of their product through this guide. The inclusion of any products mentioned within this post is entirely independent and exclusive of any relationship.
