How to Get a Head Start on the New Growing Season

This time of year can be a bit agonizing.

Spring is so close that you can practically hear the bugs buzzing and birds singing, feel the sun’s reassuring warmth on your face, and smell the cheerful aroma of blooming flowers.

But the reality is most of us will probably have a few more frosts before it’s officially time to enjoy gardening outdoors again.

Luckily, you can get a little taste of spring by starting your garden now. In fact, you should start your garden now, because an earlier start means an earlier harvest!

I just lamented that it’s not yet time to start gardening. Then I encouraged you to start your garden.


Here’s the thing: we may not be able to start plants outdoors yet, but we can start growing indoors. In this post, I’ll show you how to get a head start on the spring growing season by doing just that.

Discover When You Should Start Seeds for Your Garden

When to Start Seeds Indoors

Most seeds’ packet labels suggest when to plant based on your growing zone. But in case yours doesn’t—or in case you’ve lost the packet—here are general suggestions for a few popular crops.


  • Broccoli, kale, lettuce, and other frost-tolerant greens, start seeds six weeks before your final frost date, and transplant seedlings outside four weeks later.
  • Cucumbers, melons, squash, and other hardy fruiting crops, start seeds a couple weeks before your final frost date, and transplant seedlings outside four weeks later.
  • Eggplant, peppers, tomatoes, and other frost-sensitive fruiting crops, start seeds about four weeks before your final frost date, and transplant seedlings outside six weeks later.

If you’re not sure when to expect the final frost for your area, try this frost date finder tool.

Tower Tip: With the Tower Garden Grow Lights Kit, you can garden indoors any time of year. That means you can start your plants as early as you like and simply move them out once spring arrives.

How to Start Your Seeds Indoors

5 Things You Need to Start Seeds Indoors

To improve your odds of successfully growing strong, healthy seedlings indoors, make sure you have the following tools and materials.

1. Quality seeds

If you want to start your own plants from seed, you’ll first need the seeds. And for best results, you should use high quality seed.

When it comes to sourcing seeds, I’m partial to SeedsNow and High Mowing—both offer organic, non-GMO seed. (Seed swapping is always a fun option, too!)

That said, seeds for basil, cucumbers, eggplant, lettuce, peppers, and tomatoes ship with every Tower Garden. And if you ever want to restock your supply of those same seeds, you can find them here.

Recommended reading: 17 Sources for Seeds and Seedlings »

2. Growing medium

Next, you’ll need something to put your seeds in. Tower Garden uses rockwool—which helps plant roots efficiently absorb both water and oxygen—and vermiculite as a growing medium.

If you’re using rockwool, it’s a good idea to soak it in pH-balanced (shoot for the 5–6 range) water before planting, as rockwool tends favor the basic end of the pH scale. After about 30 minutes of soaking, you can plant your seeds.

Wondering how many seeds to plant? Generally speaking, the smaller the seed, the more of it you should plant.

When in doubt, reference your seed packets. Instructions for planting are often included on the label.

After planting the seeds, lightly cover them with dry, coarse-grade vermiculite. (This helps keep moisture around the seed, improving germination rates.) Then gently sprinkle a little water over the vermiculite.

Tower Tip: For smaller seeds, fill rockwool cube holes only half full with vermiculite.

3. Propagation container

Seeds—check. Growing medium—check. Now, where are you going to put your freshly planted seeds?

Well, if you order a Tower Garden, it comes with a propagation tray. So that’s pretty handy.

But if you’re starting seeds without it for some reason, here are a couple other options:

  • DIY. Most any clean container that can hold a little water should work. I often use an emptied plastic container that originally held salad greens from the grocery store.
  • Buy. If you’re planning to start lots of seeds at once, consider purchasing a propagation tray with a clear dome and heat pad. (These are available online and possibly at your local gardening store.) The benefit of using a dome and heat pad is improved germination. The heat pad evaporates water in the tray, and the dome holds the moisture in. This creates the humid environment that seeds love.

4. Water and nutrients

Is your container full of rockwool cubes ready? Add less than half an inch of water (ideally water that’s filtered and not too hard, softened, or chlorinated) to the tray.

Check your seeds daily and add more water as necessary to ensure the tray doesn’t dry out.

Once seeds sprout (which can take a couple weeks depending on the plant and propagation conditions—again, reference your seed packet label here), you can start feeding them with a diluted Tower Garden Mineral Blend nutrient solution.

Adding about one capful of Mineral Blend A and one capful of Mineral Blend B—along with the water you typically add—every other day should do the trick.

5. Light

Before your seeds germinate, they don’t need light. So you can put them wherever it is convenient. (I often place mine on top of my refrigerator—which doubles as a makeshift heat pad!)

But as soon as you see sprouts, you should put your plants where they’ll get lots of light. In most cases, this means using grow lights.

You may be wondering, “I’ve got a sunny window, so do I really need grow lights to start seedlings?”

Simply check your seedlings, and they’ll tell you.

Either they are rich in color and compact in stature, or they are pale and spindly. If your seedlings look more like the latter, they probably aren’t getting enough light.

I recommend lighting your seedlings with either tube fluorescent lights or compact fluorescent lights, also known as CFLs. Both are inexpensive, energy efficient, and easy to find.

Another nice thing about fluorescents is they don’t put off much heat, so you can place them as close as three inches away from your seedlings. And doing so will help your plants grow compactly, which is a good thing.

Tower Tip: If you decide to use fluorescent lights, make sure they’re “cool-colored” (i.e., in the 4,000–6,500K range—learn more about light color here), as this type of light best encourages vegetative growth.

How to Move Seedlings Outdoors

Moving Seedlings Outside

When it comes to moving your young seedlings outdoors, a couple of items may make the process go a little smoother. The following will protect your plants should you get an unexpected, light frost.

  • Manage the temperature inside your Tower Garden with a submersible heater. The water temperature should stay between 65–85˚F.
  • Cover your seedlings with a Weather Protection Blanket to shield them from chilly nights. (Bonus: This UV-resistant blanket can also protect your plants from heat stress in hotter months.)

Once you’ve got these, you’ll be ready to harden off and transplant your seedlings.

How to Harden Off Seedlings

If you’re like me, you’ll eagerly await the day you can transplant your seedlings outdoors. But for best results, you should introduce your plants to the outside world gradually. This is a process called “hardening off.”

When you start seedlings indoors, they know only the stable, safe conditions of your home­, where they enjoy consistent temperature, ideal lighting, and protection from pests.

If you pluck them out of that little utopia and stick them into an environment with wind, rain, temperature fluctuations, insects, and so on, they’ll get stressed.

That stress can stunt your seedlings’ growth. In fact, it could even kill them. And clearly, if that happens, your reasons for starting seeds early become rather moot.

So hardening off is important. Fortunately, it’s pretty easy, requiring only a few minutes each day starting one week before transplant day.

Just follow these steps:

  • For seven days, set your seedlings outside in a relatively protected area (e.g., somewhere with indirect sun and little wind exposure).
  • On the first day, leave your seedlings out for only an hour. Then each following day, add an hour and start to expose them to more sunlight.
  • On the final day, your seedlings will have experienced seven hours outside. After that, they should be hardy enough to transplant.

Tower Tip: To start the hardening off process even earlier, aim a small fan—set on low—at your seedlings as they grow indoors, and gently touch their leaves and stems a few times each day.

How to Transplant Seedlings

Once you’ve hardened off your seedlings and they’re about three inches tall with roots growing from the rockwool, you can transplant them. Plant one seedling per growing port in your Tower Garden by gently pressing the rockwool cube in until it touches the base of the net pot.

Tower Tip: Starting a Tower Garden full of new seedlings? Be sure to use half-strength nutrients for the first month. That formula is: 10mL of Mineral Blend A + 10mL of B / gallon of water.

In as early as a month, you may be enjoying your first harvest!

Summary + More Resources to Prepare for Spring

Starting seeds indoors allows you to get a head start on the growing season—which means earlier (and ultimately more) harvests. The first step of starting seeds is finding out when your final frost should hit. Then, based on that date, start planting!

Here’s a recap of what you need to get started:

  1. Quality seeds
  2. Growing medium
  3. Propagation tray
  4. Water and nutrients
  5. Grow light

You may also want to pick up a submersible heater and Weather Protection Blanket, as these can help your plants as they transition from indoors to out.

Starting seedlings is only the tip of the iceberg! There’s much more that goes into garden planning and preparation.

Here are a few materials to help you along the way:

Questions? Let’s continue the conversation below.

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