18 Seed Starting Tips for Beginners
Starting Seeds is a lot easier if you have some tips that will keep you on the right track.
Did all your seedlings die? Do you struggle to successfully seed start each year? I had trouble with it as well until I learned all of these seed-starting tips for beginners.
Like anything else, starting seeds indoors is trial and error. You learn from mistakes and figure out what works and what leads to the sprout death. Ideally, you learn from others’ mistakes and have better successes at the start.
I put together my favorite seed-starting tips. These are things I wish I knew from the start. Yes, not everything is budget-friendly (it IS possible to do this all cheaply though!), but after growing a garden for nearly 12 years, I know what works. My hope is that these tips work for you as well.
Related: Starting Seeds on a Budget: 9 Easy Steps
18 Seed Starting Tips for Beginners
1. Don’t Start Seeds Too Early
Seeds that stay too long inside may begin dying. So, use the USDA hardiness zones to figure out your typical last frost date.
I always tell people to talk to local gardeners as well. The map may tell you that your last frost date is a certain time, but local gardeners know best. According to the USDA, my last frost date is at the end of April, but I know frosts often happen into May.
Use this date to count backward when determining when to start seeds indoors. Seed packets will how many weeks before this date you should begin the seeds inside.
2. Use the Right Soil for Seeds
Garden soil is not for seed starting. Seed-starting soil should be sterile; don’t scoop dirt from outside and bring it inside for your seeds. It should be light and airy with the right nutrients necessary for early plant development.
Don’t stress! Grab a bag of seed-starting soil from the store or use an organic brand, such as Espoma.
3. Get Decent Pots & Trays
For years, I used Styrofoam cups for seed starting with holes punctured in the bottom. These cups WILL work, so if you have a very tight budget, grab a few sleeves.
However, I suggest grabbing some decent pots and trays that are usable for several years. These will have drainage holes already cut into the bottom. I prefer trays because they have drainage trays, making bottom watering easier.
No matter what you select for planting, it needs to be deep enough for root development. I suggest having several sizes because you will eventually need to move up pot sizes OR add more soil to the growing plant.
Related: 7 Best Seed Trays and Pots for Starting Seeds at Home
4. Clean Your Trays & Pots Yearly
ALWAYS clean seed trays and pots yearly. Not all seedlings live to meet the garden, dying due to viral, fungal, or bacterial issues that live on plastic. I suggest scrubbing thoroughly with dish soap or anything antibacterial to ensure they’re ready for the new growing season.
5. Drainage MATTERS
I mentioned you NEED drainage holes in the bottom of your trays and pots; this is NOT negotiable. Always check the drainage tray as well. Sometimes, too much water will sit in the tray for days without you realizing it.
Plants, especially seedlings, detest soggy feet; who can blame them? You only want water standing in the tray after bottom watering, the most effective way to water seedlings. I talk more about bottom watering a few tips down.
6. Use New Seeds or Plant MORE!
Some gardeners tell you that you MUST order new seeds yearly. This is a lie.
Seeds are good for years. I have seed packets from 2019 and 2020 that grew well last year. The trick is understanding the problem with “old” seeds.
Over time, the germination rate decreases with the age of a seed. It’s impossible to determine by date or by looking at a seed if it’ll germinate.
So, what can you do with older seeds? Plant more. It’s that simple. In general, gardening experts say seed germination rates will decrease by 10% yearly. You should always put at least two seeds in a pot because no one has 100% perfect germination. So, if you use older seeds, put a few more into the tray to overcompensate for the age.
Believe it or not, you CAN move seedlings after they pop out of the soil. It just takes time and being careful.
Related: 13 Reasons Seeds Don’t Germinate & What You Can Do
7. Pre-Moisten Your Seed Starting Soil
Once you open a bag of seed-starting soil, you’ll notice how light it is. You MUST pre-moisten the soil before planting. Otherwise, once you plant your seeds, the soil will take time to absorb the water, and chances are it will come out of the tray or pot.
It’s always a mess.
So, I put it into a clean bucket or large mixing bowl and then pre-moisten before filling my trays and pots. It works so much easier that way!
8. Provide Humidity for Germination
Germination requires more humidity than regular seedling growth. The best way to achieve this is to have a dome over your seedling trays or pots. Another option is to put plastic wrap over the pots until germination occurs.
The ideal humidity for germination is 75% and higher. It’s not easy to measure that inside of a dome, but the more humid, the better your seeds will sprout. Once they sprout, remove the dome. Seedlings prefer humidity between 35-55%.
You can use a small hygrometer to check the humidity near your seedlings.
Related: How to Germinate Seeds Quickly in 6 Steps
9. Don’t Forget The Right Lights!
A normal light bulb won’t help seeds grow. Ideally, the bulbs you use need to have 2,000 lumens. They don’t HAVE to be growing lights. For years, I used clamp shield lamps and grow light bulbs over top of the plants. They did FANTASTIC.
I recently switched to plant shelves with full-spectrum grow lights. I love how organized it makes me with four shelves and included lights. However, it is not necessary to purchase any sort of put-together set-up!
10. Avoid Overwatering Your Seeds
Overwatering leads to the death of seedlings, often causing dampening-off. No plant wants soggy roots that sit in a puddle. Sitting in water prevents roots from absorbing much-needed oxygen.
Check your seedlings daily, but DON’T water daily. They don’t need watered every day or every other day, in most circumstances.
11. Bottom Watering IS Superior
The BEST way to water seedlings is with bottom watering. This only works if your tray or pots sit in a tray with a rim.
Bottom watering is just like it sounds; put the water into the tray and set the tray or pot into the water. The roots will absorb the needed water through their roots. You avoid overwatering or splashing soil out of the containers.
12. Make Sure It’s Not Too Cold!
I’ve made some mistakes over the years, and one of them is seed starting in an unheated shed or basement. Seedlings prefer temperatures around 70 degrees F, especially during germination.
Now, I seed start in our school room, around 68 degrees F. I use a heat mat for seedlings to encourage germination and remove it once the seedlings sprout.
I learned the hard that way coldness is not their friend. One year, a BUNCH of my tomato seedlings turned purple. No, they weren’t purple tomatoes; they were far too cold.
Related: 5 Reasons for Purple Stems on Tomato Seedlings
13. Gradually Raise Your Lights
As your seeds sprout and grow, you will gradually increase the height of your grow lights. In the early days, the light should only be 2-4 inches away from your plants. If you notice legginess developing, lower the lights. That means they’re rapidly growing to reach the light!
Over time, you’ll move the light further away from the seedling. It’s important to remember closer in the beginning, and further away at the end.
14. Fix Leggy Seedlings ASAP
Ok, so your lights were TOO far away, and now you have leggy seedlings. Are they ruined?
NO. Most of the time, you can FIX leggy seedlings; I’ve done this plenty of times. I shared a detailed tutorial on how to fix leggy seedlings and preventative tips previously, so make sure you read it.
Don’t toss those seedlings into the compost. They ARE savable, in most cases!
Related: How to Fix Leggy Seedlings & Prevent It in the Future
15. Pot-Up Before Your Plants Struggle
What’s the deal with potting up or up-potting? Do you HAVE to do it?
Yes. In most circumstances, you must change pots throughout your plant growth. As your plant grows, the roots will as well, and in most trays, they simply run out of room. You run the risk of ending up with root-bound seedlings, causing stunted growth or death of the plant.
I prefer starting my seeds in trays and moving them to pots as the plants get larger. Small 4″ plastic pots are great for this stage!
Related: How to Fix Leggy Seedlings & Prevent It in the Future
16. Strengthen Their Stems with Air & Movement
As your seeds grow, you want to prepare them for the big world outside, and it’s not a still world. Whenever you water your plants, gently run your hands over them, moving them side to side in a sweeping motion.
Over time, add a fan to the space and let them have air movement for a few hours a day. They will experience wind when they go outside, and the wind can break stems. Gradually strengthening their stems with movement will increase the likelihood they survive outside.
17. Know When It’s Time to Move Seedlings Outside
You’ll move your seedlings outside eventually, but doing so before the right time will kill your plants. After all this hard work, this isn’t when you want to see plant death.
Seedlings that cannot handle frost shouldn’t be moved outside until after the danger of frost is gone. If you leave seedlings outside and it frosts, they will die. Some seedlings enjoy a bit of cold, while others, like tomatoes and peppers, won’t live through the cold.
18. Harden Off Your Seeds Properly
Once it’s time to move them outside, ensure you properly harden off seedlings.
Start by putting them outside in a shady area for one to two hours. Each day, increase the length of time they are outside and their sun exposure. This doesn’t have to be a perfect science; no timer is needed.
I typically start by putting them outside in the late afternoon one day and move the time earlier and earlier each day. Soon, you’ll leave them outside overnight a few times. At that point, they’re ready to live in the outside world!
