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New Growth


6 secrets for how to grow plants from seed

This is the eight step in Planter Box Gardening 101 series: Grow Seedlings with Success! 

Step-by-step – here’s how to grow plants from seed.

First, there are lots of great reasons to grow plants from seeds.  The best reason is that, dollar for dollar, seeds are much less expensive than buying starts from a nursery or mail order catalog.  You can get HUNDREDS of plants for around a dollar, vs. one plant for a few dollars.  I love to collect seeds from my own plants each year to multiply your investment.


Growing plants from seed is also a joy-packed process.  I love watching those little babies go from tightly packed seeds to big, beautiful blooms each year!  It’s fun to give away your baby plants to friends in the Spring or sell them in a neighborhood yard sale.  After all, who can pass up a 3-year old selling lavender plants?!

Do you have a TON of seeds that you need to organize?  Be sure to check out how I organized ALL my seeds in a Seed Catalog!  I share my step-by-step DIY guide. 

Growing Plants

"To plant a garden is to dream of tomorrow." — Audrey Hepburn

Why are seedlings SO hard to grow?


Like many of you, I’ve had my share of total failures with learning to grow plants from seed.  I have failed to grow plants from seed for these primary reasons:


  • Starting them too early in the spring (if you’re anxious to plant, work in your Garden Journal instead!)

  • Letting them dry out

  • Overwatering

  • They get “leggy” from the wrong light and don’t survive outside

  • Taking a trip/leaving them alone too long

Thanks to all those failures, I’ve finally found the formula of “secrets” that ensure healthy plants when I grow plants from seed.  Here are my secrets–I hope they help save you time, money, and heartbreak!  

Secret #1:  A Dedicated Home for Your Starts

I’ve tried everything – starting in the greenhouse, on a counter top, in the garage, in a spare bedroom.  We all have our own parameters and constraints we need to navigate so here’s my secret:  It’s important to have a dedicated place to grow plants from seed that won’t be problematic for the next few weeks.  Dedicate ONE SPOT where you can create the perfect growing conditions without disturbing the seedlings. 


If you are moving your trays around every few days, it’s hard to ensure your plants are getting what they need.  

My seed-starting space is the counter top in an insulated workshop in the garage.  I have a small space heater in there that keeps the room between 55F and 65F.  This, along with my lights and heat mats, create the perfect growing temperature.

Secret #2:  Lots of Light!


Sunlight in the early Spring is scarce, even in my brightest windows. I have killed SO many seedlings because they didn’t have enough sunlight!

Seedlings need 14-18 hours of mixed wavelength light to grow strong, healthy, and not “leggy” (thin and weak).  They grow leggy when they are reaching for light; help them out by giving them plenty of light!

I mounted a 4 foot shop light that holds two fluorescent bulbs.  I use one cool light and one warm light bulb, attempting to mimic the sun’s wide spectrum of light for the plants to access.

Notice that I use a timer on my lights.  This ensures they get enough light during the day, and experience a period of darkness.  You can use the same type of timer you use for holiday lights.  These are very inexpensive - shop them here.

Mounted shop lights.webp

Secret #3:  Seedling Heating Mats


These are my FAVORITE secret of all!  Seedling Heating Mats.  They have made ALL the difference between success and failure for me and seedlings.  If you want to grow plants from seed, you MUST try these mats!  They keep the soil around 70F, which is perfect for getting little seedlings started.  Too many times I’ve killed seedlings by forgetting to turn on the heater, or neglecting them for a day.  

These mats are inexpensive, water-resistant, and ensure that my seedlings have idea growing temperatures.  I bought this two-pack (which fits PERFECTLY under the Jiffy Starter Greenhouse 72-pack).  10″ x 20″ is the perfect size for my needs.

I leave these mats on around the clock for about two weeks when I first grow my plants from seed.  These are not on a timer.  Others may say you don’t need to keep the soil warm past a few days, but I do and it works great.  They are silent, low voltage, and worth EVERY penny.  

seed heating mat pack

Secret #4:  Choosing the Right Growing Media

Which media you choose depends on where you live and what you’re growing.  Because I live in an arid climate (and everything dries out quickly), I prefer to use a wet mini-greenhouse environment.  I have a ton of success with the little Jiffy Starter Pods, and LOVE the Greenhouse Starter Kit with 72 cells.  They are easy to water from the bottom (you don’t want to dump water over tender little babies), and tend to be more sterile than other brands I’ve purchased.  Did I mention I LOVE the 72-cell Starter Greenhouses?  These fit perfectly on my seedling heating mats AND perfectly beneath my grow lights.  Everyone gets equal amounts of light and heat.  

Be sure to download my FREE Seed Planner for this Jiffy Tray; it’s a free PDF that will come straight to your email!  This helps take the guess work out of “What did I plant!?”

seed tray planting tracker freebie

Before I started my seedlings in my Jiffy greenhouses, I soaked my trays in hot water with a tablespoon of bleach.  Then I let them air-dry before adding the dry pods and soaking them in water.  It’s important to ensure that all bacteria and disease is killed off before trying to start your seedlings.  They have a hard enough time surviving; don’t make it harder by letting germs or garage dust get in their way, too!

Keep a close eye on your starter pods, though!  I found this one right in the middle and pulled it out immediately. You can see a fuzzy something growing across the top.  It will definitely impact the growing seedling, and I don’t want it to spread to my other healthy sprouts.  Hey, 1 out of 144 is not bad!

fuzzy pod.webp

Secret #5:  The Right Amounts of Water


Watering is a major element of keeping seedlings alive. My Jiffy greenhouses do a lot of this work for me.  I watch to see when the pods turn light brown and slightly dry on top.  That signifies they need a topping off with water.  I then add it to the bottom of the tray using a skinny-nosed watering can.  The pods soak up the water and distribute it to the roots, without damaging the tender seedlings.


This helps protect the tiny sprouts while getting water up the top.  I lost hundreds of plants over the years to my media drying out; that’s because I live in an arid climate and I wasn’t using the right tools!  Decide what’s best for you, based on your growing conditions.


Once I move my starts to the greenhouse for hardening off (see my experience with choosing a great starter greenhouse), I switch to using a garden sprayer like this to water water them.  I prefer to give them a light mist (instead of a gush of water) in these early stages in the greenhouse.


You don’t want your seedlings sopping wet, nor do you want them to dry out.  That’s why the next secret, Secret #6, is perhaps the MOST important!  

Secret #6: LOTS of Attention!


This is the MOST important secret of them all if you want to grow plants from seed.  During the first few weeks, don’t neglect your seedlings, even for a day.  

Some of this year’s plants began sprouting at 3 days!  That included my mini pumpkins, giant sunflowers, and french lavender seeds.  These large varieties shot up to the greenhouse ceiling within 5 days.  Once all seedlings have sprouted, you can remove or angle the lid so sprouts can keep growing higher and stronger.  This helps prepare them for the Great Outdoors!  Be aware, however, that having the “greenhouse effect” lifted means they may lose their water faster.  That’s why it’s important to check them daily to ensure they have enough water and nothing funny is happening (damping off, etc).  

A Note about Stratification


Plants are a funny thing.  Some seeds can be placed right into a growing medium and grown without issue! Others prefer a “cold snap” to trick them into sprouting.  I never have issues with veggie seeds needing stratification, but some flower seeds (all those penstemons, for example) need a cold snap to trigger them to grow.

One example I have is this – I planted some Showy Milkweed (Asclepias speciosa) from the Monarch Foundation one year and was super frustrated to see that none of them germinated.  The next year, POOF!  I had milkweed all over the garden – in the places where I’d tried to start my seeds the previous year. It turns out that Showy Milkweed needs a period of stratification to germinate. After a cold winter, it was ready to grow (and now it's everywhere!). 

So don’t give up on seeds just because they don’t germinate right away! They may surprise you.  Also, you can create a “false cold snap” with a process called stratification.  You can place the seeds in a cool refrigerator (I like to use the one in the garage in which we store fizzy water and extra milk).  I leave my seeds in the door in a Ziploc bag for 4-6 weeks before planting; that usually does the trick.  

My parents live in Minnesota. Each fall, my dad collects Common Milkweed seeds (Asclepias syriaca) from the garden and stores them in the freezer! He has for years. I never understood it as a kid, but now I certainly do. Then they plant them in their favorite corner of the yard, and they're ready to bloom each year!

Be sure to check and see if your seeds need stratification!  That can help you avoid a headache and a long wait for germination.

A Word About Soil Block Makers for Seeds


Every gardener has their preference of what type of soil should be used to start seeds. If you decide to not use seed starter pods like those from Jiffy, then I highly encourage the use of Mel's Mix and a soil block maker. Read all about how to simply make Mel's Mix here. Mel's mix actually works pretty well with soil block makers.

In recent years, I've experimented with using a soil block maker, which is a very handy invention!

Pros of using a soil block maker: Low cost after the investment, you can use any soil you like, less transplant shock since you go from Mel's Mix in the tray to Mel's Mix in the garden.

Cons of using a soil block maker: It's a messy process (which I kind of like), getting the right consistency takes practice, and it is much more time-consuming than Jiffy pods.

Time to Start Planting From Seed!

As temperatures heat up in my Zone 6b region, I move my babies out to my greenhouse during the day to help harden them off.  Check out my post about how I successfully use my greenhouse to extend my growing season.  Farmer’s Almanac teases me that I have “year-round frost risk!”  

Be sure to harden off your plants before moving them to their permanent location outdoors; otherwise they can go into transplant shock and all that hard work will be for nothing.  

Feel free to share your best seedling tips in the Comments below!

Best of luck and happy planting!





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