How to Grow a Garden with Seed Starting
Intro: A Beginners Guide to Seed Starting
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Starting plants from seed can be one of the most cost-effective ways to establish your garden and flower beds. However, it can also be the most daunting. It took me years of trial and error before I finally started getting the hang of it. Even still, I sometimes struggle depending on the plant variety and how busy I am. Seed starting your plants can be very time consuming!
I used to think it was as simple as sticking the seeds in soil, giving them light and water, and like magic I would have plants. Let me save you some heartache and frustration by letting you know it is most certainly not that easy…
…most of the time.
However, I will tell you that you’ve come to the right place. I will break down the seed starting basics step by step to get you seed starting on the right foot. Hopefully, I can help you avoid some of the mistakes and errors I made when I was getting started.
Let’s dig in!
What You’ll Need
So before we get into the nitty gritty of seed starting, let’s talk about some basic things you’ll need.
Lighting
You don’t need fancy expensive grow lights to get your seeds to grow, but you will need light from some source. If you have a bright south facing window, that will do just fine! If you don’t have window space, I recommend these lights from Amazon.
Seed Starting Soil
A good seed starting soil is excellent at retaining moisture but is also porous so it can drain well. You’ll need your seeds to stay moist enough for germination and root growth, but not too moist that they rot. You can purchase pre-made mixes from a store or make your own using a mixture of equal parts peat moss or coco coir, perlite, and vermiculite. If you have or make your own compost, adding in an equal part of compost will also promote good growth.
Seed Starting Tray
You’ll need something to start your seeds in, however, don’t feel like you need to buy a fancy seed starting tray. I’ve started seeds in a wide variety of containers. Old food storage containers, cardboard egg cartons, salad mix containers from the grocery store, you name it. Just make sure that whatever you use has good drainage. You will also need a way to cover your seeds. If you’re not using a seed tray like this one, you will need a clear bag or plastic wrap if your container doesn’t have a lid. I also recommend having a tray to set your seed tray or container in. This helps keep water off your tables and floors and allows you to bottom water once your seedlings emerge (more on this later).
Watering Can or Mister
Personally, I like to use a mister when my seeds first emerge rather than a watering can. A mister provides a gentle stream of water so that the seeds and very young seedlings are not disturbed. This hand pump mister is one of my favorites, but a spray bottle will do the trick too. You can also get fancy and use a decorative mister like this one. If you choose a more decorative mister, be prepared to make several trips to the faucet.
Fan For Air Movement
As your seedlings develop, you’ll want to get them near a fan or breeze to keep them gently moving. This will help promote strong stems and keep them from flopping over. One that oscillates like this one would do the trick.
Labels
If you’re planting more than one type or variety of seeds, it’s always a good idea to label them. You could use little plastic labels like these or popsicle sticks. Additionally, I like to use these markers. They won’t fade in the sun like regular permanent makers. There’s nothing worse than having the sun fade out your label leaving you wondering what you planted.
Optional: Heating Mats
I’ve grown many different plants from seed without using heat mats, but a heat mat can help your seeds germinate faster. The tricky part with heating mats is that you will need to be conscious of how dry your soil gets. While helpful, they are not necessary and can be cause for frustration with beginners. I’ll touch more on the use of heat mats later as well. If you are ready to try heat mats, this two pack gives you the most bang for your buck.
Seeds
Probably the most fun item on this list is your seeds. Just remember to not go too crazy when shopping. Seeds don’t last forever, and the more you buy, the more you need to plant. A good quality seed will get you the best germination rate, and the most robust plants. Some of my favorite places to shop for seeds include:
Not every seed is going to have the same requirements for germination so it’s important to read your seed packet for instructions.
Some seeds will need light to germinate. These will need to be sown directly on top of the soil without being covered. Certain seeds will require a period of cold stratification before they’ll germinate. For these types of seeds, you can place the seed packet in your refrigerator for a few weeks before planting to achieve this. Additionally, some seeds need to soak in water overnight before planting. While other types of seeds you can just stick in the soil and wait for them to sprout.
Johnny’s Selected Seeds gives excellent planting instructions both on their website and on the seed packets. If there are no instructions, you can always do a quick search online to find tips from other seed sites for planting.
Determining Frost Dates & When to Start
How do you know when to start your seeds? If you start your seeds inside too early, they’ll quickly outgrow their space before you can plant them outside. If you start them too late, you won’t have blooms or a harvest at the right time during the season. Thankfully, there’s an easy way to figure out when you should start.
First, you’ll need to look up your expected last frost date. You can easily do this by going to www.almanac.com and entering your zip code/postal code. It’s important to keep in mind the date you’re given isn’t a guarantee. Frost dates are calculated using years of weather data, and as you know, the weather can be unpredictable. For example, my expected last spring frost according to the Farmer’s Almanac is around May 7th. This very well could be correct depending on the year, but I know from years past there have been several nights up into the first week of June when temperatures dropped below freezing. There’s no harm in getting your plants outside on your expected last spring frost date, just know you may need to keep an eye on the weather each night and proactively protect your new plants until overnight temperatures are consistently above freezing.
Once you know your last frost date, you can calculate when to start your seeds indoors. I’ve always started seeds about 6 weeks before my last frost date and this has worked well for me. Plants are typically mature enough to go outside between 4-6 weeks after you start them.
For example, since my last frost date is May 7th, I should start my seeds around March 26th. For seeds that take longer to germinate or reach maturity, I may start those 7-8 weeks before my last frost date. Your seed packet will typically tell you the days to germinate, the days to maturity or both. As a rule of thumb, a plant that reaches maturity in 60-90 days is a quick growing plant. A slower growing plant may take 100-150 days to reach maturity. You’ll need to do some experimenting, and over time you’ll work out a good timeframe for your own seed starting.
Now that you know when you’ll be starting your seeds, the next steps are fairly easy.
Preparing Your Soil & Seed Tray
Whether store bought or self-made, you’ll need to pre-dampen your seed starting soil. I like to make sure my soil is damp enough by using the squeeze test. For perfect soil, you should be able squeeze a clump in your fist and it should keep its shape. When squeezed, the soil should not ooze water out between my fingers or crumble. If it crumbles when you squeeze, add more water. If you have water dripping through your fingers, add more dry soil.
Next I like to wash and sanitize my seed starting trays. A small splash of bleach in a sink full of water should do the trick. This step is especially important if you’re using trays from previous years. Due to the damp conditions seeds germinate in, there’s a possibility that bad bacteria and fungus are still in the trays. Washing trays ensures that any bad bacteria or fungus can’t be transferred to your new seedlings and hinder their growth.
Once you have the soil dampened and trays cleaned, you’ll need to pack the soil into your tray. There is a bit of a science to this. Make sure you don’t pack it in like a brick. Too tight of soil could cause your seedling’s roots to be unhealthy. If you pack it too loosely, there will be too many air pockets which can cause your soil to dry out too fast. Packing too loose can also cause difficulty when transplanting. A seed cell that is packed too loosely will fall apart when you go to transplant it, and the roots could end up broken or disturbed. Cells that are packed moderately firm will hold together nicely for transplant. It takes practice, but once you get the hang of it, packing seed trays will be like second nature to you.
Planting Your Seeds
Now that your trays are prepped, the next step is to plant your seeds. Now is the time to grab your labels too. Also ensure your seeds are ready for planting per the instructions on the seed packet. I like to pour my seeds into a dish so that I’m not accidentally dumping the entire packet everywhere.
If you’re using a seed starting tray with individual cells, you’ll need to make an indent in the center for the seeds. Otherwise, if you’re using another type of container, you’ll need to do the same, but evenly space out your indents 1-3″ apart. If you’re planting more than one variety per tray, it’s easier to place your labels ahead of time. This way you know where to start and stop with each seed variety.
*As a quick tip, make sure any seeds you plant in the same tray have similar germination timelines and growth rates. If you’re not sure, keep your seeds varieties each in their own tray.
Carefully take your seeds and individually place one per cell or indent on your tray. If they require light to germinate, leave them uncovered and lightly mist over them so they stay in place. If the seed doesn’t require light to germinate, take some extra soil and sprinkle it over the top of your newly placed seeds. Some seeds will also need to be placed deeper per the seed packet instructions. Once you’ve filled your tray, gently mist the surface to prevent them from shifting or blowing away.
Be sure to place your tray cover on as soon as you’ve finished watering them in. If you’re laying plastic wrap or using a clear bag to cover the trays, use toothpicks to keep the cover off the soil and give them room to start.
Caring for Your Seeds Before They Germinate
At this point, if you’re using a heat mat, you’ll want to place your seed starting tray directly on top of the heat mat and turn it on. It’s very important with heat mats to check every day, and sometimes multiple times a day, to ensure your soil isn’t drying out too quickly. Bottom watering your seeds will also help create a more humid environment making it more difficult for your soil to dry out.
At this point, it’s not quite just a waiting game. You still have some minor care and maintenance to keep up with to ensure your seedlings get a good start. Depending on the type of variety you may see germination in a few days or in a few weeks. During this time, it’s important to make sure the soil stays damp for the seeds. You don’t want the soil too wet, but if you notice it starting to look dry, or there is little to no condensation on your lid, you may need to open it up and give them a quick mist.
Once you do start to see germination occurring in about 25-50% of the cells, crack the lid to get airflow on your seedlings. If they spend too much time in overly humid conditions, they run the risk of rotting. If you completely remove the lid before they have time to get established, the soil will dry out too quickly. Once you see closer to 50-100% germination, completely remove the tray cover.
Caring for Your Seedlings
Now that you have seedlings to take care of, it’s important to make sure they get plenty of light. If they weren’t already in a sunny window or under grow lights, move them to an area that gets plenty of direct light. If you are using a window, regularly rotate your tray so that you don’t have shadows falling on the same seedlings every day. This also helps prevent seedlings that lean towards the window. A quarter turn in the same direction each day will do the trick.
Make sure the soil stays moist as well. When ever possible, try to water from the bottom of the tray. This will promote roots to grow downwards towards the moisture. Bottom watering is easiest when you have a seed starting tray that comes in three parts: a bottom tray, seed cells, and a cover or humidity dome. You can still achieve this by ensuring your seed container has holes for drainage and then placing it in a slightly larger one without drainage holes.
If you’re using grow lights, you’ll want to start with your lights fairly close to the seedlings. In the beginning, keep your lights about 3-5″ off the top off the leaves. This will help you prevent your seedlings from getting leggy and stretched out. As your seedlings continue to grow, raise your lights with their growth so they aren’t getting burned by the lights.
Now is the time to set up your fan nearby as well. I like to keep my fan at its lowest breeze rate around 5′ away from my seedlings to start. The constant, gentle breeze will help strengthen the stems which produces strong, robust plants.
Hardening Off Your Seedlings
After a few weeks of good healthy growth, you’ll want to start to harden them off before moving them outside. This step is crucial to keeping your plants alive. Your seedlings have been in a perfectly maintained, cozy environment for the last several weeks. If you immediately transplant them in the ground outdoors, you’re going to shock them. This step can be quite cumbersome, but it is extremely important so don’t skip it!
I recommend starting with an hour a day, take your trays outside and set them in a mostly sunny location. A mix of part shade and part sun to start will be perfect. Do this for several days and slowly work your way up to several hours a day in full sun. This hardening off period will acclimate your seedlings to their new environment and make transplanting easier on you and your plants. After your anticipated last frost date, you can transplant your new plants in the ground. Just keep an eye on the weather and should frost be expected in the forecast, don’t worry. You can go out and cover your young plants to keep them protected.
Conclusion
Once outside and fully transplanted in your garden, don’t forget to continue to care for your new plants. You put the time, effort, and energy into growing them over the last several weeks. Continuous care will ensure you can get the most enjoyment out of them!
Most importantly, don’t beat yourself up if things don’t go the way you hoped they would go. It took me years of trial and error to get a system down for seed starting. To this day I still have times where it just doesn’t go the way I want it, or I make crucial mistakes that ruin my seedlings, so it can happen to the best of us! What do you struggle with for seed starting? I’d love to know your seed starting struggles and triumphs in the comments below!
