When you’re gardening in the Salt Lake Valley, you know that starting seeds in Utah can feel like you’re starting too early. 
Most years, we’ll still have snow on the ground.
But whether or not there’s snow on the ground, spring planting season will come, and we want to make sure you feel prepared.
One of the most enjoyable steps toward getting our veggie gardens ready is starting seeds in Utah. After all, the growing season is right around the corner! There are a few things to consider when starting your seeds indoors, including:
- What type of veggies you want to plant
- When to start germinating your seeds
- How to care for your seedlings
In this blog post, Glover Nursery experts will explore all of these topics. Hopefully, this allows you to start your seeds in a timely fashion and have a successful harvest season!
What Type of Seeds to Plant
First, let’s talk about how to select seeds for your garden.
The most important thing to consider before starting any seeds is, what do you like to eat? As much as we all love to grow tomatoes, if you do not like to eat tomatoes, then do not give them your precious garden space.
So, start with a list of veggies that you enjoy eating, or flowers you want to grow.
Once you have your list, it’s important to look at the amount of space you have available. While you might have pumpkins at the top of your “must grow list”, if you have a small space, they’re not going to be a good fit.
If you need help figuring out how to strategize smaller spaces, come chat with our team here at Glover Nursery. We can help you with some basic planning suggestions to maximize your growing area.
For larger gardens, you have more options but we do have a few suggestions below that can help you make the most out of your growing area.
Once you have considered these factors, you can choose the specific varieties of plants that you would like to grow. To find out more about specific plant varieties, consult a gardening book, online gardening resource, or one of our experts here at Glover Nursery.
For both small and large garden areas, some of the most popular veggies to start from seed are tomatoes, peppers, lettuce, cucumbers and peas. Though the list of what you can easily and successfully grow from seed is significantly longer.
What You Will Need
Starting seeds doesn’t require a lot of specialized supplies, though you will want to invest in some good grow lights to ensure your seedlings get adequate light during the darker months.
Once you have selected an area to start your seeds and set up the grow lights to help get them started, many gardeners are successfully starting seeds in Utah using items they already have at home. Common supplies include:
- A sterilized seeding flat with drainage holes
- Labeling materials (popsicle sticks and a Sharpie can work!) You absolutely want to make sure you label your seeds; it’s too easy to get them mixed up when they’re tiny.
- A full spectrum light source that can be within 6-8” over your seeding trays.
- 3-4” containers for larger seedlings
- Seed starting specific growing medium.
It’s also important to have a consistent watering routine. Most gardeners choose to use a seed starting soil blend as it helps with moisture and heat retention, which are both necessary for seeds.
You can also make your own mix, just be sure to use soil that has not been exposed to any disease or fungus, as that will kill the seedlings.
Regardless of your containers or labels, the most important factors are providing consistent moisture, proper warmth, and sufficient light during early growth.
When to Start Seeds in Utah
Next, we move on to the all-important question of when to start your seedlings. Here at Glover Nursery, we recommend taking the last average frost date and counting backward as to how long that seed would need to germinate.
According to the Farmer’s Almanac, the average last frost date in West Jordan Utah is April 25. Many people, colloquially speaking, wait until Mother’s Day to plant their veggie garden.
So, to get a good start ready for transferring outdoors, we have an easy equation to help you. We recommend looking at how long something takes to germinate and adding a couple of weeks of growth onto that before transplanting it into the garden.
Here’s a quick equation.
(Average Last Frost Date – Germination Time) + 2 Weeks = When to Start Your Seeds
Now that you know what to plant and when to plant it, you may be interested in learning how best to take care of your ‘lil baby starts.
How to Start Seeds in Utah
Sowing the Seeds
Begin by lightly moistening your soil before adding to the growing container. If you fill the container with dry soil, the seeds will not have a firm surface when they’re placed and may settle a bit too low into the dry soil, which can affect their ability to germinate.
Additionally, the moist soil helps seeds settle without shifting during the first watering.
Once the seeds are placed on the moist soil surface, add another layer of soil to cover the seeds. Be sure to read the seed packet instructions for planting depth, in general seeds only like to be covered lightly with soil, where some need to be 3-4x the depth of the size of the seed.
Once the top layer of soil is placed over the seeds, very gently press the soil to nestle the seeds a bit. This will prevent them from washing around during the first watering. Then, you can go ahead and gently water the new seeds, which will help kick off the germination process.
For seeds to germinate, they also need to be kept warm, and they need about 8 hours of light to set off that little spark of life. If you are starting seeds in a shed or garage, you will want to check the temperature of the space to make sure it’s warm enough for the seeds to start. In general, the soil needs to be kept at 65 degrees or a little warmer.
Additionally, you will want to have grow lights ready to help give that necessary light to the seeds to create the right conditions for germination to happen.
Lastly, label containers clearly as you plant. Keeping track of this early prevents confusion later!
Watering Seeds
Seeds need consistent moisture, warmth and light to germinate. However, too much water can create significant problems.
The best way to gently water is with a water mister or diffuser to avoid any high pressure from displacing the seeds. Allow the water to saturate the soil, but do not leave the seeding container sitting in standing water, as this can cause root rot and invite disease.
For maintenance, check moisture daily without overwatering. The soil should feel damp, but never soggy. Containers will feel lighter as they dry, so softly lifting the tray can give a lot of information about the moisture level.
However, the best way to determine if the soil needs more water is the old gardener’s trick of sticking your finger in the dirt. If it’s dry, give it some water. If it’s wet, don’t.
After the seeds have germinated and the seedlings are poking up, you can monitor them visually as well.
Though sometimes the visual cues of overwatering are very similar to underwatering, following the same protocol of weighing the seed tray and feeling the soil will help you quickly determine if the seedlings are dry or if they’re too wet.
If they’re dry, water immediately to saturate the soil. If they’re wet, be sure to let them dry out, as they may have become infected with disease or are rotten from sitting in too much water.
What to Do When Seeds Germinate
Once seedlings emerge, remove any covers immediately. Seedlings need airflow to stay healthy. You will need to adjust the growlights as the seedlings grow. The light should be close enough to prevent stretching, but with enough room to allow the plants to grow.
Some people find having their grow lights on the bottom of a shelf makes it easy as they can just raise the shelf a peg at a time, but there are many successful methods available.
Seedlings grow quickly at this stage, so it’s best to monitor moisture and light daily. Try to avoid sudden temperature changes near windows or vents.
Thinning Out Seedlings
Thinning is necessary when multiple seedlings grow in one container. Crowded seedlings compete for light and moisture. Use scissors to cut weaker seedlings at the soil line. Avoid pulling the seedlings out, though. This can disturb their roots.
Leaving only one strong seedling per space improves airflow, reduces disease risk, and promotes healthy growth. This step will make a noticeable difference as strong roots develop when plants have enough room.
Transplanting Seedlings
Once the weather is ready for planting season to begin, you can also check that your seedlings are ready to transplant after they have developed at least 2 sets of true leaves. True leaves appear after the first small seed leaves, called cotyledons.
In general, most transplanted veggie starts should be planted so the root system is at the same depth as the surrounding soil. However, there are some veggies that can develop adventitious roots, which means the starts can be planted up to the first or even second set of true leaves to encourage an even stronger root system.
Tomatoes are best known for this type of planting. Some Brassica and peppers have been able to develop extra roots with this method, but it’s not a guarantee, so if you are not sure about your specific variety of vegetable, err on the side of caution and do not plant too deeply.
After this, water lightly after transplanting and give them some time to recover from the stress.
Hardening Off and Moving Outdoors
Before planting outdoors in Utah, seedlings must adjust to outdoor conditions. This process is called “hardening off”. Start by placing seedlings outside for short periods, then increase exposure gradually over one to two weeks. Protect them from wind and direct sun at first.
However, the weather can change quickly here in the Salt Lake Valley. Avoid hardening off during cold snaps or strong winds. Gradual exposure reduces shock and stress and allows them to adapt more easily.
Seed Starting Practices by Plant
Onions  Starting seeds in January or February should be done indoors. Transplant outdoors around late April to early May. | Lettuce
Keep indoors around late February or March. However, you can kickstart it earlier if seedlings can be protected from heavy frost outdoors Transplant seedlings in late March or Early April once they’re about a month old. | Peas
Best planted outdoors as early as late February up to early April. You can plant it directly in the garden if the soil can be worked. |
Utah Seed Starting FAQ
What kind of soil is best for starting seeds in Utah?
In Northern Utah, soil choice matters because cool early-season conditions already slow seedling growth. The soil should be light, clean, and able to drain well.
Garden soil is not ideal for indoor seed starting because it compacts easily and may contain harmful organisms. Reused soil can also carry diseases from previous seasons. Starting with fresh soil helps prevent these common early problems.
Some gardeners prefer using a seed starting mix, but this is entirely optional. A good quality potting soil made for indoor containers can also work well. Avoid soils with added chemical fertilizers, since young seedlings are sensitive to excess nutrients.
Too much fertilizer can damage roots before plants are established. So it’s best to focus on cleanliness and drainage instead of feeding early.
What are some common seed starting mistakes to avoid?
Starting seeds indoors in Utah? One of the most common mistakes gardeners make here is overwatering. Cool indoor temperatures slow evaporation, which means soil stays wet longer. Excess moisture can cause seedlings to rot near the soil line.
This is why you should always allow containers to drain fully after watering. Never let your seedlings sit in standing water.
Not having enough light is another frequent issue, especially during Winter to Early Spring. The shorter days and low sun angles make window light unreliable. Seedlings grown in this environment become tall and weak.
Inconsistent temperatures may also cause problems, particularly near windows or vents. Overcrowding seedlings reduces airflow and increases disease risk.
Can all seeds be started indoors?
Not all seeds are good candidates for indoor starting. Though it’s possible to successfully transplant veggie starts with great success.
Some plants prefer to grow where they’re seeded. Root crops like carrots, beets, and radishes do not transplant as well as other veggies are known to do. Peas are known to perform better when sown directly into the garden, though we have seen plenty of peas grow hearty harvests from transplanted starts.
Warm season crops are better candidates for indoor starting. Tomatoes, peppers, eggplants, and some herbs benefit more from early indoor growth.
Should I soak seeds before planting?
Some seeds benefit from soaking before planting, especially those with hard outer seed coats. Soaking helps water reach the seed more easily and speeds up germination. Larger seeds often respond best to this method.
In Northern Utah, soaking for 1-2 hours may help when soil temperatures are slow to warm.
However, not every seed needs soaking. Many small seeds germinate just fine without preparation, and some seeds just need light to germinate without getting covered or soaked.
Can I reuse seed starting trays?
Yes, seed starting trays can be reused if they’re sterilized properly. Old containers may carry disease from previous growing seasons. Washing the trays removes soil residue and organic buildup. They also help reduce the spread of bacteria or fungi.
Try sanitizing the trays with a diluted bleach solution and rinse thoroughly with water. Then allow the trays to air dry completely before planting.
Get Help Starting Seeds in Utah
By following these simple tips, you can ensure that your seedlings have a happy and healthy start to the growing season. Now you know when to start seeds in Utah!
The seeds have arrived at Glover Nursery, and we are so excited for the gardens, which will soon house the rows and rows of seedlings from the packets we have available now.
If you’re overwhelmed or looking to try something new this year, we encourage you to stop by and chat with our knowledgeable team. We love pointing out our favorite seeds for our local climate here in the Salt Lake Valley. We may even have one or two surprises for the seasoned gardener.
Seedlings need a lot of care, but if you follow these simple tips, you can ensure a happy and healthy start to a healthy and hearty harvest!
