Starting Seeds Indoors

Tips and Tricks for Starting Seeds Successfully

Cabbage Seedlings
Pixabay

Starting seeds properly can make or break your entire growing season! Here are our best tips and tricks for starting seeds indoors.

Before You Start Seeds

  • Be seed savvy. Obtain seed catalogs from several companies and compare their offering and prices. Some of the regional companies may carry varieties better suited to your area.
  • Make a list of what you’d like to grow. A good rule-of-thumb is to imagine your garden one-quarter the size that it really is. This allows for good spacing practices! See our Growing Guides for inspiration.
  • Prepare for some losses. Though it’s good not to plant too much for your garden space, it’s also good to assume that some of your seeds won’t germinate, or that they will inexplicably die off later. Plant a few extra, just in case.
  • Team up with a neighbor and share seeds if you have leftovers!
  • Don’t start your seeds too early, especially tomatoes. Most annual flowers and vegetables should be sown indoors about 6 weeks before the last frost in your area. Check out our Planting Calendar to see when to start seeds (indoors and outdoors) in your area.
  • You may have to soak, scratch, or chill seeds before planting, as directed on packet.
  • Use clean containers. Most seed catalogs offer seedling flats, peat pots, and other growing containers, but egg carton compartments make good containers, too. Be sure to poke holes in the sides near the bottom of the containers you use in order to allow excess water to drain.
  • Label your containers now! There’s nothing more frustrating than forgetting what you planted.

Tomato seedlings

How to Start Seeds

  • Fill clean containers with a potting mix made for seedlings. Use soilless peat moss and mix in equal parts vermiculite and perlite to hold enough water and allow oxygen to flow. Don’t use regular potting soil.
  • Pour soilless mix into a large bucket and moisten with warm water. Fill your containers to just below the rim.
  • Plant your seeds according to your seed packet. Most seeds can simply be gently pressed into the mixture; you can use the eraser end of a pencil to push in seeds. When planting seeds, plant the largest seeds in the package to get the best germination rate.
  • Cover containers with plastic. Prick holes with a toothpick for ventilation. Water as directed.
  • Water newly started seedlings carefully. A pitcher may let the water out too forcefully. A mist sprayer is gentle but can take a long time. Try using a meat-basting syringe, which will dispense the water effectively without causing too much soil disruption.
  • Find a place in the kitchen where there is natural bottom heat—on top of the refrigerator or near the oven. (Move the tray if the oven is on, as it may become too hot.)
  • Seeds sprout best at temperatures of 65 to 75°F (18 to 24°C).
  • When seedlings appear, remove the plastic and move containers into bright light.
  • When the seedlings get their second pair of leaves, prepare individual pots filled with a potting mix with plenty of compost. Move the seedlings carefully to the new pots and water well. Keep pots out of direct sun for a few days.

Seedlings. Photo by Sergii Kononenko/Shutterstock
Photo by Sergii Kononenko/Shutterstock

Moving Seedlings Outside

Before transplanting seedlings to your garden, you’ll first need to do something called “hardening off.” This will prepare the seedlings for the harsh realities (i.e., climate) of the outside world! 

  1. During their last week indoors, withhold fertilizer and add water less often.
  2. Seven to ten days before transplanting, set the seedlings outdoors in dappled shade that is protected from winds for a few hours each day, gradually increasing their exposure to full sun and windy conditions. This is the hardening-off period.
  3. Keep the soil moist at all times during this period. Dry air and spring breezes can result in rapid transpiration. If possible, transplant on overcast days or in the early morning, when the sun won’t be too harsh.

Watch our video on hardening off for more info:

After the hardening-off period, your seedlings are ready for transplanting. Here are a few tips:

  • Set transplants into loose, well-aerated soil. Such soil will capture and retain moisture, drain well, and allow easy penetration by seedling roots.
  • Soak the soil around new seedlings immediately after transplanting.
  • Spread mulch to reduce soil moisture loss and to control weeds.
  • To ensure the availability of phosphorus in the root zone of new transplants (phosphorus promotes strong root development), mix 2 tablespoons of a 15-30-15 starter fertilizer into a gallon of water (1 tablespoon for vining crops such as melons and cucumbers), and give each seedling a cup of the solution after transplanting. 

Learn More

See when to start seeds in your area with our location-based Planting Calendar.

Here’s another “quick and easy” method to plant seeds. Also check out our video on the top tips for starting seeds.

Need more advice? See Vegetable Gardening for Beginners to learn how to plan your best garden yet, and use the Old Farmer’s Almanac Garden Planner to do so!

Get Your Special Pass -- Access to the World's Most Beloved Almanac

Reader Comments

Leave a Comment

Your help with gardening.

Thank you!

Miracal-Gro

I am starting an herb garden and purchased Miracle-Gro potting mix before discovering this website. Is it okay to use to start my seedlings or should I buy the recommended vermiculite and perlite. Having little experience at growing any advice would be much appreciated!

Potting Mix

Yes, that potting mix should be just fine. It likely contains vermiculite and perlite already, so just keep an eye on it to make sure it stays moist. If the mix also contains chunks of bark and other materials, you may want to sift the large pieces out in order to give your seedlings an easier time getting started (otherwise, they’ll have to grow around these obstacles). Happy planting!

starting seeds hardening off

More question then comment but do commercial green houses harden off the plants we buy from green houses?

Greenhouses

In most cases, it’s safest to assume that the seedlings you buy have been grown indoors and will still need to be hardened off before being planted in your garden. They may not need to be coddled quite as much as home-grown seedlings, but it depends on the conditions inside the greenhouse they were grown in and how similar they were to local outdoor conditions.

My seeds germinated sooner than expected

I thought i did everything right. Two weeks ago I started my seeds indoors. I checked my "last frost date" (April 15), time til plant outdoors (6-8 weeks), days til germination (14 days average) checked it all on the calendar, grew with lights. I guess maybe i did it too well. My seedlings are HUGE! They aren't leggy, but are outgrowing their starting trays, How should i plant them up? What size peat pots should I use and then how do keep them well lit? Also can anyone advise on fertilizer after they are potted up?

Go Kelly Go!

You sure did everything right! Maybe you started a little early, but that sounds like a success story to me. The size of the pot depends on two things: what is in it, and how long before they go into the garden. I would suggest that with the great results you're having to use the biggest pot you can, because once the roots start poking through the peat they need to go into the ground - and at the rates your little babies are growing April 15th is a long way off. As far as lighting, if you can keep them under the same lights that would be best. Otherwise put them in a south-facing window. When you transplant them use good soil (personally I like Fox Farm's "Happy Frog") and you shouldn't have to fertilize them for a month or so.

Root Riot plugs

I have had GREAT success using Root Riot plugs for my seedlings. They keep moist but not wet - just the perfect moisture content for the seedlings. I also have the tray on a heat mat in a west-facing window so they get morning sun, but not all-day sun. Plus their initial waterings are made with a solution of diluted Mychorrizae (sp?). Even with seeds that are a couple years old, I still get strong germination rates.

Sprouting Tip For Hard Shelled Seeds.

Have you ever had peppers or tomato seedling leaves get stuck in their hard seed coat after germinating? I have, and it is not easy to remedy once it happens. My solution to this which I have been using for years is to plant the seed with the root tip UP, not down. When the seed root emerges, it makes an immediate U-turn downwards. What emerges above the soil is the middle of the seed stem in an inverted U shape. The leaves are still in the seed coat below the surface where it is still moist. Eventually the inverted U pulls the leaves up and out of the soil with the seed coat still buried. Works every time. Not so helpful on seeds that are difficult to tell which end is the root end (round seeds).

Planting seeds under plastic.

If I plant seeds under plastic do I take it off when seedlings appear? Also, do I have lights on only in the daytime?

When they reach about 1 inch

When they reach about 1 inch no more then 2 inch, take off the dome, the longer you keep the dome on, the taller and weaker the seedlings will grow, the longer they are the more apt they are to brake in the wind and such.

seedlings

Hello I have planted my seedling they were planted Friday April 22. Of course they have not sprouted yet but I have accidentally over watered them and was wondering what I could do or if I could put them in the sun to absorb the water. Please help

watering seedlings

Does your seedling tray/pot have drainage holes? Make sure they are not clogged. (Stick a toothpick up the hole and wiggle around.) Are you using loose, well-draining soil? If not, you really have to repot. Don’t move the tray/pot to the sun until the roots are healthy again. Don’t water again until the surface of the soil is dry to the touch. However, do not try it out either or that’s just too much shock. Do not fertilize until the plant has recovered. We hope these tips help.

 

question about seed timing in chicago.

I was wondering if its still early enough to plant seeds for tomato plants in the chicago area? I started some seeds prior to this month but some had become leggy and dampening had affected some of them. so I was wondering if im able to still plant seeds and have decent size plants by the start of june or end of may?

thanks

mildew

I have old seeds and wanted to see if they are viable, so I started them indoors early. Some of them have germinated, but I am noticing blotches of mildew on the soil. Did I hear peroxide and water will take care of this? If so, what is the ratio? Thank you for your help.

mildew on soil

The most common cause of mildew on soil is high humidity. Increase the air circulation by lifting the lid (or whatever is covering your seedlings). See if you can scrape off the mildew without harming the seedlings.

We would not recommend hydrogen peroxide on the plant at this time. It’s more of a container cleaning agent before you even start.

When starting seeds, you want to be sure that your starting medium is viable, new/fresh, and soilless, which being very light discourages humidity and encourages circulation.

We hope this helps.

Seed starts in Western Ontario

Hello! When should I start my veggie seeds here in this part of Ontario, Canada? If I started now, I'd expect it to be about 7-8 weeks before the last frost.

Most vegetable and annual

Most vegetable and annual flower seeds can be started indoors about 6 weeks before the last frost. Check our Planting Dates for Seeds chart. Link is at the top of this page.

 

seedlings

What do I do if my seedlings are flowering but they cannot be moved outdoors for 3-4 weeks.

Starting cucumber seeds

At what point can I start germanating my cucumber seeds for my first garden. I live in south east Texas so I have no idea about last frost, so I want to be ahead of game but don't want to start to soon thanks

cucumber seed starting

You might be interested in our cucumbers page here:

http://www.almanac.com/plant/cucumbers

On it, it says:

  • Cucumbers are seeded or transplanted outside in the ground no earlier than 2 weeks after last frost date. Cucumbers are extremely susceptible to frost damage; the soil must be at least 65ºF for germination. Do not plant outside too soon!
  • For an early crop, start cucumber seeds indoors about 3 weeks before you transplant them in the ground. They like bottom heat of about 70ºF (21ºC). If you don’t have a heat mat, put the seeds flat on top of the refrigerator or perch a few on top of the water heater.

To find out your frost date, go to this page and type in your zip code:

www.almanac.com/gardening/frostdates/

Then, count back 3 weeks from the last expected spring frost date to find the date to sow the seeds indoors. Good luck!

 

Perennial Seed starting

Do you have an Indoor seed starting chart for annual/perennial flowers ?

School Garden - starting some plants indoors -

Hello! I am a teacher-librarian in a K-8 school in Bowmanville, Ontario. Our school is starting a habitat area on the school yard with some native plants (eg woodland sunflower, and hopefully a raised bed for veggies. I want to transform part of my large library space into an indoor growing space so we can start seedlings in the spring. What will I need in the space to start seeds indoors. It is in a corner with about 10 feet of two storey windows that face west and one window about 3 feet wide that faces north. Do I need special lighting?
Also, is it possible for me to grow anything indoors through the winter? Herbs, maybe?
I don't have a lot of background in gardening but lots of enthusiasm and a school full of students who want to learn to be responsible, sustainable citizens in suburbia.
Thanks for your help. I have appreciated reading the comments you left for other folks.
Brenda

How early is too early

Hi,

I am in Ottawa, Ont. Canada.. Zone 5a.

I am curious of early is too early to start plants indoors. I started some pepper plants and tomato plants beginning of Dec with hopes to grow mature plants and transfer them outdoors in april/may.

I would still keep them in pots while hardening them off for 2 weeks before transplant.

I will also start new seedlings in Feb to be safe but wanted to know if my December plants would help me get a bigger headstart or bigger headache than worth.

and yes.. i have bigger pots and room in the house.

starting seeds early

If you start seeds too early, it can make it difficult for the plant to survive transplant shock when transferred outdoors, even after they were hardened off. Also, keep track of the days to maturity. For example, if you have a determinate tomato plant that matures in 80 days, and it was growing indoors since mid-December, then it might produce fruit (if pollinated) before it gets transplanted out in April/May. It would probably be too hard on the plant once it is in fruit, but you can certainly try it: at that point, it might be best to just keep growing it indoors (especially if you have a greenhouse). Indeterminate tomato varieties might be better than determinate, as they might continue to flower and set fruit after recovering from transplant shock.

Tomato seeds from last summer

Tomato seeds from last summer reseeded in my vegetable garden and 4-5 of them look very healthy. Do you think they'll produce fruit, or since they were in the ground with very cold temps (in MD) over winter, should I throw them out?
Thanks for your feedback.

Hi Dana, Don't throw them

Hi Dana,
Don't throw them out. If you have room in your garden let them grow and hopefully you'll have a nice harvest later this summer. If these plants are from heirloom varieties you should get some tasty tomatoes.

I started some flower and

I started some flower and vegetable starts indoors and one morning woke to them all eaten. What could have done this? I have looked for worms, but none around. No bugs of any kind to be seen.

Pages