9 Indoor Seed Starting Mistakes Gardeners Make And Tips To Avoid Them

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Starting seeds indoors isn’t hard and it can save you a lot of money. But that’s only if your plants grow, thrive and produce in your garden for you. It’s having a high germination rate and keeping your seedlings alive and healthy that can be tricky.


Starting seeds indoors is a fun way to save money and get a head start on your growing season. But there are 9 common seed starting mistakes made by beginner gardeners that can ruin your seedlings. Learn how to to avoid these seed starting problems and grow a thriving garden with these easy tips. #gardening #seedstarting #homesteading

When I was a new gardener I made a lot of mistakes. Sometimes I was lucky, and other times these mistakes caused me to lose my seedlings. It can be heartbreaking to see your little plants dying when you worked so hard to get your garden started.

But I didn't give up and I want to encourage you not to give up either! Starting your own seeds is just like learning anything new, it takes time and practice. It's really worth it though as it opens up a wide world of new vegetable, herb and flower varieties that you can't find at your local nursery. 

Thankfully these seed starting mistakes can be easily avoided. These simple tips will help you start your own seeds and have them thrive.

1. Not Enough Light

Plants that don’t have enough light start to look leggy. This means that they grow very tall, but have thin stems and little foliage. They are desperately trying to reach the stronger light.

You may think that your home is bright and filled with natural light but chances are you don’t have enough natural light in your home to grow healthy seedlings. Even if you have a large south facing window, it often just isn’t enough. However, this is easily fixed by using artificial lights.

You can buy grow lights that are made with the perfect indoor light for growing seedlings or for a more budget-friendly option use some fluorescent shop lights. A common recommendation is to use 1 cool fluorescent light and 1 warm light together to provide a full spectrum of light to your plants.

However, I find that using 2 cool bulbs seems to work just as well as using 1 cool and 1 warm. I have multiple grow light setups and only one of these uses real grow bulbs. It was the first indoor lighting setup I bought years ago and while I love it, I find that seedlings grow just as well in my homemade grow light setups.

Hang the fluorescent lights from chains so that you can easily raise them up as your seedlings grow. Keep the lights 2 - 3 inches above the tops of the seedlings for optimal growth. Once your seeds have sprouted keep the lights on for 12 to 16 hours a day. The easiest way to do this is to use a timer to turn the lights on and off automatically.

2. Under Watering or Over Watering Seedlings

One of the most common problems when starting your own seeds is over watering and under watering. Either of these can be the end of your seedlings.

When you first start your seeds you need to keep the seedling starting soil moist. You don’t want it soggy and dripping wet or the seeds will rot. Likewise, if the soil is to dry the seeds just won't sprout.

It’s very helpful to remoisten the seed starting soil a little before you start to plant. Fill up a bucket or basin with your soil and add enough warm water to make it just hold together loosely when you squeeze some in your hand.

After filling your planting containers, and planting your seeds add more water to the plant tray on the bottom and let it soak up just enough to be damp without being soggy. Bottom watering is an easy way to water newly planted seeds and seedlings without disturbing them.

Make sure to check your plants at least once a day to see if they need watering. This is especially important if you are using heat mats under the seed trays.

If you want to save time on watering seedlings these self watering seed trays are a big help!

3. Planting Too Deep

Another common problem when starting seeds are that they are planted too deep. Your seed package should tell you how deep to plant your seeds but a good guideline is to plant seeds as deep as twice their width. It’s always better to err on the shallower side if you're not sure though. Planting seeds too deep can make them use up a lot of energy just trying to sprout to the surface.

For seeds that need light to germinate, you will want to press them down gently on your soil. This will make sure they are in contact with the planting soil but are still exposed to the light.

4. Starting Seeds Too Soon

One of the biggest problems when starting seeds indoors has to be that you start your seedlings too soon. I know it can be so hard to resist, especially if you live in a cold area with long winters like I do but waiting until the right time to start your seeds is the best thing to do.

Many of the seedlings normally started indoors like tomatoes and peppers just don’t like the cold. Exposing them to cold growing conditions will stress the plants and can cause them to be set back or worse die.

Most plants are ready to be moved outside 4 to 6 weeks after they’ve been started indoors.

5. Cold Soil

Seeds need warm soil to germinate. 20-26 C (68-79 F) is best for most seeds. Think of it this way, when do seeds germinate outside? In the spring right! Seeds naturally start to sprout when the soil has reached the right temperature to tell it’s safe to grow. When you start your own seeds indoors keeping the soil warm is the best way to have a high germination rate.

The easiest way to do this is to use seedling heat mats. These are water resistant heat mats that you place under your seedling starting trays to warm the soil. These only need to be used until your seeds have sprouted after that you can put them away. Seedlings are happy to grow in cooler temperatures then the seeds need for germination.

6. Labeling Problems

If your starting more than 1 type of plant it can quickly become a problem if they are not labeled well. I’ve had years where labels have been lost or moved or the writing was worn off from watering. This isn’t a big deal if you're only growing 1 type of tomato but what if you have 20 varieties and hundreds of plants?

Ok, ok, really even if your growing just a few plants you still need to know which plants are which. Besides being nice to know they might need different care and supports in the garden, such as a bush or vining tomato plant.

So my best advice is to keep it simple when it comes to labeling seedlings. I use Sharpies, the fine point or ultra fine points are my favourite. To make the actual labels popsicle sticks are my go to every year. They are budget-friendly and easily available.

Before using them I like to cut them in half, this makes them the perfect hight if your using plastic dome covers on your seedling trays. Even if your not it makes them go farther.

I place a plant label in every cell pack inside my seedling tray. I find this is especially helpful if your using 1 tray to start multiple varieties. With only one label it’s easy for it to get knocked over or go “missing” with little ones helping.

7. Not Hardening Off

Seedlings are delicate, really they are just baby plants and like all babies, they need to be cared for gently.

When your seedlings are ready to go outside you just can’t move the trays outside and leave them in the sun or plant them directly into the garden. Your seedlings have never been exposed to strong sunlight or winds and just planting them outside can set them back or more likely kill them.

There is a simple solution though, it’s called hardening off your plants. The basic idea is that you are exposing your plants to the elements slowly and giving them time to adjust.

This means that you will spend 7 to 10 days placing your plants outside for a longer time each day until they are strong enough to handle being planted in your garden.

8. Getting Overwhelmed

It’s so easy to become overwhelmed when you're starting your seeds. It’s been a long winter and you’ve had so much fun pouring over the seed catalogs. Your seed wish list has grown, and grown, and grown.

The problem is that we can end up buying so many seeds that we can never care for them all properly. We may not have enough room to start them all indoors, let alone fit them into our garden.

Each year we try to practice self-restraint and not try too many new varieties in the same year. If you are a beginner, I suggest that you start by taking your time and trying a few varieties instead of 20+ varieties of tomatoes… Yes, I’ve done it too!

9. Giving Up

What is the biggest mistake gardeners can make when starting seeds? It’s giving up.

Yes, starting your own seeds can be a lot of work and a real pain when things don’t go right. It takes time and attention but it’s really worth it.

Even if you’ve made a lot of mistakes and lost a lot of plants this year or in past years it really is worth it to keep trying. 

Starting your own seeds opens up a huge world of fruit and vegetable varieties you just can’t buy locally.

My favourite tomatoes are unusual varieties like Pink Tiger, Solar Flair, Elizabeth, and Indigo Rose and I’d never find these for sale locally. Even if you’ve made mistakes starting seeds don’t give up, it’s so worth it when you take that first bite from a sun-warmed heirloom tomato.

Looking for more garden tips? Try these to help get your garden off to a great start!



Kim Mills is a homeschooling mom of 6 and lives on an urban homestead in Ontario, Canada. Blogging at Homestead Acres she enjoys sharing tips to help you save money, grow and preserve your own food.

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