If you started seeds indoors and they are not germinating or they have sprouted but they are failing to thrive, this should help you troubleshoot the problem.
This is part of a series, Indoor Seed Starting for Beginners | Sow Indoors Grow Outdoors, where I walk you through the process from seed to garden. It’s all the information I wish I had when I was getting started.
Troubleshooting Seed Germination Problems
This is an excerpt from the ebook
Seed Starting for Beginners: Sow Inside Grow Outside
sharing everything you need to know to start your own garden plants from seeds indoors.
All Thumbs Are Green
It makes me crazy when people say they do not have a green thumb and cannot grow anything, as if there is some sort of supernatural curse on them, causing even the best efforts to fail.
Every garden mishap has a cause. With a bit of thought and patience it is often possible to figure out where things went south. And, no, it’s not a curse. It’s just that something essential to growth—or a few things—were not sufficient for seeds to grow. It’s usually simple. You are not cursed. You can do this.
- At What Growth Stage Did The Problem Occur?
At What Growth Stage Did The Problem Occur?
1Seeds Never Germinated
Seed Quality and Freshness
If your seeds never sprouted, it could be one or a combination of these factors:
- Did you start with fresh, good quality seeds? Seed packets often have dates indicating freshness.
- Are you sure they were viable? It’s easy to test most seeds in moist paper towel to see if they will germinate.
The more recently seeds are harvested, the better they germinate. Some seed packets show sow-by dates. And, no matter how reliable the source, there are always a few duds in the lot (that’s nature). See if the expected germination rate is listed on the package. Get fresh seeds from a trusted source and always plant a few extras.
Get Seed Starting for Beginners and start today
Sowing Method and Care
- Did you sow them as directed?
Every type of seed has its own preferences. Read your seed packets for specific instructions. Some require presoaking, prechilling, or a scratch of their coats to encourage germination. Others can be directly sown. Do not skip the advice given: it’s often key to success.
From there, it matters how deeply they are sown. Most are sown just twice as deep as the seed is wide. Others—not many but some—go on the surface because they need light for germination.
Those seed packets provide a lot of valuable clues! This shows how to read seed packets and grow like a pro.
- Did you keep the growing medium moist all through the germination and growing stages?
When we store seeds, they are dormant. To sow them, we wake them up with warmth, moisture, and then air and light. If a newly sown seed is not consistently in contact with the moist growing medium, it may dry out and die. Nice, even moisture—not too wet or dry—is the key.
- Did you use growing medium intended for seed starting?
We use special seed starting mixes for sowing seeds indoors because they provide just what the seeds like in these special indoor conditions. Seed starting mixes are lightweight and make it easy for the seed to receive moisture without having to fight to grow. Garden soils and other potting mixes can be too heavy for the wee seeds and may introduce pathogens (no, thank you).
Here’s a list of recommended supplies for sowing seeds indoors including the best growing medium to use.
- Was your growing space warm?
There are two different temperature groups for seed starting: seeds that like some warmth, and others that like more warmth. If your room (and growing medium) is too cold or warm, seeds may struggle, die, or never germinate.
Most seeds germinate nicely with indoor temperatures of 65-75° F (18-23° C).
There is not one ideal temperature for all seed types but a good compromise is between 65-75° F (18-23° C). For specific recommended soil temperatures, see this chart for flower seeds and go here for vegetable seeds.
2Germination Started and Stopped
Your seeds may have started off nicely but then, blah! Any changes in environment can bring everything to a halt. Temperature swings, drafts, lack of light or inconsistent moisture—or some combination—are possible causes.
Once you start the germination process, never let your seedling mix dry out.
3Seedlings Seemed Fine but Then Stopped Growing or Wilted
Again, temperature swings could be the cause. Some warmth is good, but too much heat and seedlings wither.
Another cause is a group of pathogens called damping-off that like wet, cool conditions and kill or weaken seeds and seedlings. This explains the disease and provides damping-off prevention tips.
The name damping-off is strange, but the condition is fairly easy to recognize. Your seedlings will either turn brown and wither, or start looking like they were kicked in the knee and they gradually fall over and die.
If you think this might be it, google it and check images. And when in doubt, remove the affected plants and growing medium.
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4Plants Still Growing but Appears Weak, Thin, or Leggy
The most common cause of leggy seedlings is inadequate light. If a plant must work too hard to reach light, it will stretch and become thin or leggy, and appear weak. If you are using grow lights, keep them just above the tops of the plants. If you’re growing in front of window, rotate the containers every day.
Less common, but possible is bad genes. Not all seeds from the same pack are created equal. There’s good ones and bad ones. Maybe you grew a dud. Maybe the dud had friends. Again, were the seeds fresh and from a trusted source?
Nutrition is important too. The plant is surviving on whatever its environment provides. For the first stages, the seed itself provides all the nutrition needed.
But once you have some leaves, the plant begins to need nutrition from the soil. Perhaps your growing medium, or, at this stage, potting mix is deficient—not at seed germination time but several weeks later.
If the plant has a few leaves (and light is sufficient), you could add some (very diluted) organic liquid fertilizer. Follow the directions on the container and dilute it to adapt to such a small plant. Personally I do not use any fertilizers for my indoor seedlings: their first nutrition comes with the compost added to the garden soil when they begin life outdoors.
Overheating (which is essentially the plant drying out) is really tough on plants, especially the youngsters under grow lights or at hot, sunny windows.
Were your lights positioned just above the plants without over-heating them?
Is the temperature in the room staying between 65-75° F (18-23° C)?
Is the humidity between 30-50%?
Many plants actually like a little more than this but 50% is considered the maximum we should have in our homes, otherwise mold can form.
Overcrowding also causes nutritional problems. With too many plants competing for the same resources in a tight space, someone or everyone may lose. Are your plants adequately spaced in their own containers? It’s not an issue with brand-new seedlings, but the more they grow, the more room each plant needs.
Timing matters too. You will notice on seed packets that, if a seed is recommended for indoor sowing, they will tell you how many weeks or days before your last frost they should be started.
If started too early, the plant may get to a maturity level that your indoor growing conditions cannot sustain. It needs to be outside!
Find Your Frost Dates & Hardiness Zone
- Plant Hardiness Zones | United States | Canada
These are listed on seed packets and plant tags to guide your choices.
Starting too late may not cause indoor growth problems but it can mean that there are not enough frost-free days outdoors for the plant to mature (fruit or flower).
These resources will help:
- How to Time Your Indoor Seed Sowing Just Right
- Simple Indoor Seed Starting Schedule | Free Printable
- Weekly Seed Starting Plan for Vegetable Gardens
5Weird Things are Growing on My Plants
There can be a lot of different causes for this.
- Did you start with clean and sanitary growing medium, containers, trays, and tags? And nice, fresh seeds (no mold or mildew)?
- Do you grow other plants that are also affected/infected?
Do your houseplants already have problems? Or, perhaps you brought home a new plant and did not quarantine it first?
- Do you use an oscillating electric fan for good air circulation? This can keep insects from getting to the plants.
- Did you water consistently and moderately? Dampness encourages mold, algae, fungi, and other troubles.
This has tips on keeping your seedlings happy and healthy throughout their growth stages.
Okay, that’s quite a list!
And again, it’s not a curse of a bad green thumb. There are just little things that add up. The more you do this (seed sowing and plant growing), the more knowledgeable and mindful you will become. That’s another good reason to tend to your plants every day. Even if they don’t need anything, just becoming observant of how they look and grow at each stage is useful.
Dig in again. You’ve got this.
If you want to know everything about how I start plants from seed indoors, it’s all in the ebook (below).
Seed Starting for Beginners
Sow Inside Grow Outside
by Melissa J. Will
Everything you need to get started with indoor seed starting for indoor and outdoor plants. Grow what you want—any time of year!
This ebook is a digital file (PDF format) you save to your device. It is not a physical product.
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~Melissa the Empress of Dirt ♛