Tending Your Seedlings – Watering, Fertilizing, Temperature, Mold

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Good Morning Garden Soldiers!  I can’t believe it’s already been over two months since I’ve started this series.  If you haven’t already, make sure to check out the Garden Patch™ Grow Box™ Giveaway! A super easy way to Grow Your Own Food even in small areas!!

Today, I’m going to talk about tending your seedlings and how to best nurture them to help them grow to beautiful strong plants.  As my examples, I’m going to be using my tomato seedlings.


One of the first steps you’ll need to do is to make sure you are watering correctly.  Some plants are more forgiving than others.  Below is a video I took of how to water your seedlings.  Always from below.  This was taken before my true sets of leaves had grown in.

I know, it was a bit bouncy, lol!!  If you have any questions on watering, leave me a comment or send me an email.

This year I actually started my tomato plants in a larger peat pot with only a small amount of dirt on the bottom.  For all of my other seedlings, I start them in small peat pots and as they get bigger, I transplant them to a larger peat pot giving them room to grow more before I transplant them outside.

Tomato plants are a bit different than most other vegetables.  The stem of the tomato plant can be planted deep within the dirt and will start to form new roots encouraging a stronger plant and root system.  If you have ever bought tomato plants from the nursery, they always instruct to plant the entire plant leaving only 2 inches above ground.  Last year, I actually posted a video of someone starting their seedlings in this same way to utilize the concept of developing more roots for a stronger plant.  I followed the advice and as you can see from the images above, the seedlings have grown with 2 true sets of leaves.  You can definitely tell the difference between the cotelydon leaves which nourished and fed the seedling to the plants actual true set of leaves and the onset of photosynthesis.


Now that the seedlings have grown their true sets of leaves, we can thin or cut the other seedlings in each cell so that only the strongest remains.  You do not want to pull them out as this can disturb the root system of the seedling that you want to keep.


Since these were my tomato plants, I went ahead and filled them in with dirt.  This will encourage that tall stem to start developing roots.



Now that the plants have 2 true sets of leaves, it’s time to start fertilizing the young seedlings.  In order to keep these babies organic, I feed my seedlings a fish emulsion every other week.  It’s a natural based plant food and one that you should be able to find at a local nursery.  You can also use a seaweed based fertilizer.  For the first month, I dilute the formula since the seedlings are so young.  My bottle of fish emulsion calls for 1 tsp in a gallon of water.  So naturally, I half that amount for the first month. After that I’ll go ahead and use the teaspoon/gallon ratio and only water enough so that the soil is moist and not soggy.

This is where trial and error comes in Garden Soldiers!!  You can do it!  Be vigilent of how much you are watering.  Once you find the right ratios, stick with it and write it down!  This can be the most troublesome part of starting seedlings indoors as well as watering outdoors.  A topic to come!!  I’m a stickler when it comes to watering and constantly keeping an eye on the soil temperature.


One of the best investments I have made was buying a soil thermometer.  A soil thermometer allows you to check the temperature of the soil to make sure the growing environment is at a right temperature.  If the soil is too cold, the seedlings can go dormant and grow at a very slow pace.  This can be very apparent on tomato seedlings.  If your tomato leaves turn purple underneath, this is a clear sign that the soil temperature is too cold.  You will need to either place a germinating heat mat underneath your trays or place a heater nearby.

Your soil thermometer will tell you which temps for which plants.  As a general rule of thumb, if starting your seedlings indoors try to at least keep the soil temperature at 70F.


One of the biggest reasons we want to make sure and not over water our plants is to discourage the growth of mold.  Mold thrives on damp, wet, humid conditions.  You may start to see a white thin film of mold start to develop on your peat pots.  This is not a big deal and one that can be rid of by simply sprinkling cinnamon over it.  If you start to see green mold, that’s when you know you have a problem.  The best way to avoid this is to make sure your not over watering and if you think that your conditions may be too humid, place a fan in the area of your seedlings to promote air circulation.

As you can tell, tending to your seedlings is the most important aspect to grow strong and healthy plants.  This is not something that you learn right away, but through trial and error.

If any garden soldier out there has pictures of their seedlings, please email them to me.  I would love to post a round up of people Growing Their Own Food!!!  I am so EXCITED as next week I will start to seedlings outdoors!!!  5 weeks before my frost date I can start to plant peas, radishes, spinach and swiss chard!  Spring…. BRING IT!!!

Part 1: Ordering Seed Catalogs
Part 2: Understanding the differences between Heirloom, Hybrid, GMO, and Organic Seeds
Part 3: Planting Zones, Frost Dates, and Planting Calendars
Part 4. Understanding Succession Planting
Part 5. Spring Time is Near! It’s Time to Start Those Seedlings!
Part 6. Growing Seeds Indoors Under Supplemental Lighting
Part 7. Tending your seedlings
Part 8. Methods of Urban Gardening

10 Responses to "Tending Your Seedlings – Watering, Fertilizing, Temperature, Mold"
  1. Candi says:

    Thanks for posting this! I'm afraid my little tomato plants are not going to make it. When I transplanted them into newspaper pots a few weeks ago, I didn't plant them deep enough…I'm not sure what is going on with them, but now I have about 16 viable plants vs 48…

  2. Fuji Mama says:

    This was such an educational post. So many things I did not know! THANK YOU!

  3. Foy Update - Garden Cook Write Repeat says:

    I personally don't boughten fertilizer fir my vegetables or any plant for that matter. I use compost made from kitchen scraps and leaf mold. It's great stuff and I heavily ammend (I till in about three inches a year) the soil with the same compost. The compost helps keep the pH balanaced in the soil and adds a small amount of N-P-K. Even heavy feeders like tomatos will be happy with this treatment. It's a great way to save money, improve your soil texture and content and get great produce.

  4. Teresa Bjork says:

    So it's OK to plant radishes now? Is it OK to plant lettuce and spinach, too? I'm itching to plant something outside now that my tulips I coming up. I was also wondering if I could plant tomatoes early (late April/early May) if I shelter them with a milk jug. Thanks for the gardening advice!

  5. Nicole @ Geek Turned Athlete says:

    I love it! I'm going to have to keep this post in mind when I start growing veggies after we move this summer. You are making me super excited to start my own garden!

  6. Donna says:

    These are some other Gardening Classes happening in Des Moines Soon :)

    Central Library – Beginner Vegetable Gardening Class

    Johnston Public Library – Container Gardening

    Winterset Public Library – ABC's of Vegetable Gardening

  7. Anonymous says:

    folks, awesome content
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  8. Raine Saunders says:

    Hi Diana! I have started my seedlings, finally! I had ordered from Heirloom Acres, and somehow my order didn't complete itself so I had to reorder, but I finally got my seeds just after our spring break week (final week of March), and then my son and husband and I planted them last week. It was so fun! I don't have any tomatoes, I am getting those and my pepper plants locally from two organic farms.

    My seeds that I've started are are red leaf and romaine lettuce, celery, carrots, chard, broccoli, cucumbers, zucchini, peas, and squash. I'm very excited to plant sometime just after the first week of May, provided we aren't getting any frost by then. :)

    Thanks for these great tips and the videos! I'll be back and happy gardening to everyone!

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