Photo of Sunflower seedling with words Start Sunflowers Indoors Quickly and Easily

Start Sunflowers Indoors Quickly and Easily

Picture it, you’re walking or driving through the neighborhood and suddenly you see from afar a beautiful row of Sunflowers! Who can ignore such beautiful, large, and tall plants? At The Grow Monster, we like to germinate our Sunflower seeds a few different ways in order to stagger our bloom throughout summer and fall. You can start growing your Sunflowers indoors and transplant once Spring has begun. We have been using a method to help us start Sunflowers indoors quickly and easily and I’d like to share that method with you in this article.

You can start Sunflowers indoors quickly and easily by spreading the Sunflowers on a wet paper towel. It will take 1-3 days for the seeds to germinate and then you can put them in containers or right outside after all threat of frost has gone.

If you’d like to have a whole yard of Sunflowers or just a few blooming throughout the Summer and Fall this seed starting method will produce excellent results. You can do a lot or a few and as long as you keep the paper towel wet you will have lots of Sunflower sprouts. This is also a good method to produce Sunflower micro-greens which some people enjoy putting on their salads or feeding to their chickens. Read on to learn all about how to start Sunflowers indoors quickly and easily.

Sunflower garden border.

Can You Start Sunflowers Indoors?

A lot of people direct sow their Sunflowers outside as soon as all threat of frost is gone. But, can you start Sunflowers indoors? Yes! You can start Sunflowers indoors as long as you have adequate moisture for germination and if you will not be putting them directly outside after germination you will need adequate soil, watering, and sunlight. While it’s true that Sunflowers are not the easiest candidates for transplanting, it can be done- and will be more successful the younger/smaller the Sunflower plant is. We do have a step by step article for transplanting Sunflowers you can read here if you’d like to learn more.

It is really easy to start Sunflowers indoors. All you need are your sunflower seeds, some paper towels, water, and a bag or container (ziploc-type bags work as well as take out food containers- no need to get fancy). By starting your Sunflower seeds indoors, you are able to extend your growing season, especially if you are in one of the cooler growing zones. Sunflowers are hardy in USDA growing zones 4-9 and typically take about 80-120 days to reach maturity (which means grow, flower, and seeds are ready), depending on variety. The smaller, shorter flowers will need less time while the larger, taller mammoth types need more days to maturity.

Some people have even grown Sunflowers indoors year round (not just in a greenhouse, but their living room too!) by choosing the right variety. If you want to grow the Sunflowers indoors as well, make sure you are choosing a smaller variety that won’t get very tall. Some varieties get between 1-2 ft and would be ideal to grow inside in containers (try the Dwarf Sunflowers found on Amazon here). We like to start our Sunflowers indoors and put in small yogurt containers to hand out to neighbors in the Spring. It’s a great way to meet people in your neighborhood!

Should I Soak Sunflower Seeds before Planting?

Sunflower seeds have a hard outer shell either with black and white stripes (great for eating) or shiny black coloring (great for making Sunflower oil). Since they have a hard outer shell many people ask should I soak Sunflower seeds before planting? While some people do soak them overnight or for twenty-four hours before planting directly in the ground or in containers, there is no need to soak Sunflower seeds before planting– especially with the paper towel method to start Sunflower seeds.

If you do want to soak the seeds, make sure that you soak them no more than 24-48 hours otherwise they can become too soggy and lose their viability. There are also stories going around that you soak your Sunflower seeds in order to see which ones are viable. The story usually goes that if the seeds sink they are viable and if the seeds float then they are not. At The Grow Monster, we have tested this theory and had great germination rate on those that sank AND those that floated for both the eating and the oil kind of Sunflower seeds.

We recommend if you are going to direct sow your Sunflower seeds to water them in very well vs soaking them ahead of time or starting the seeds indoors with the paper towel method. You can always choose to soak the seeds if you know you are going to be going out of town after direct sowing or starting directly in containers, but it is not necessary to do so. Sunflowers are native to North America and are considered drought tolerant and resistant to many pests. Because of this, they grow well in many different conditions and are pretty hands-off once established.

Start Sunflower Seeds with Paper Towel

You can quickly and easily germinate Sunflower seeds using the Paper Towel method. This method is good for more than just Sunflower seeds, it should work well on most seeds. The Paper Towel method is great to start Sunflowers indoors and you can use it to also succession plant your Sunflower seeds. You will need your Sunflower seeds, paper towel, water, and a Ziploc-type bag to place them in.

photo of Sunflowers, paper towel, and baggie

Once you have your materials, get your paper towels nice and wet- not soppy wet but like a squeezed out sponge. Lay the paper towels out for as many varieties of seeds as you need. If you are growing many Sunflowers, then you may need more than one paper towel for each variety. At The Grow Monster, we tend to start hundreds of Sunflower seeds so lay out a large string of paper towels still attached together to have room for all of our seeds.

Photo of Sunflowers seeds on wet paper towel to start Sunflowers indoors.

Next, you will lay your Sunflower seeds on the paper towels spreading them apart every inch or so (the seeds don’t need much room to germinate, just make sure they aren’t touching). You will then fold over your paper towel ensuring that all the Sunflower seeds are making contact with the wet paper towel. If you have a long string of paper towels, you might choose to roll them up to make it easier to keep everything together.

Sunflower seeds rolled in wet paper towel.

Once your paper towels are folded up, you can place them in a Ziploc baggie or even a shallow food container or storage basket with closed lid. You will be amazed at how quickly the Sunflower seeds germinate! We’ve had some germinate overnight but the average is about 1-3 days. You will need to make sure the paper towel stays moist while the seeds are germinating and that it stays in contact with the seeds. Once they are germinated, you can choose to direct plant them outside or pot them up in small containers (like yogurt cups, cottage cheese containers, etc) until the threat of frost is gone. Or, like us, you can give away to your friends and neighbors.

Start Sunflowers indoors in wet paper towel in baggie.

Yes, it really is THAT EASY to germinate Sunflowers!

Germinated Sunflowers on wet paper towel photo.

Sunflower Succession Planting Plan

Since Sunflowers can take between 80-120 days to reach maturity, you may want to start Sunflowers indoors if you have a shorter growing season. In addition, you may want to practice succession planting in order to stagger your blooms and have Sunflowers blooming all season long from Summer through Fall. Since you will need to wait to direct sow outside until threat of frost is gone, it is beneficial to start Sunflowers indoors at various intervals and then transplant outside when the time is right.

Some of the smaller, shorter Sunflowers take less time to fully mature so you might not want to start those too early indoors. Some of the larger, taller Sunflowers take much longer to mature but starting too early indoors may make transplanting harsher on the plant. You will want to think about what date your last frost occurs in your growing zone, check out the map below, and start Sunflowers indoors 2-3 weeks before your last frost date.

Use the Paper Towel method to germinate a portion of the total amount of plants you would like each week. For example, if you would like 100 Sunflowers, you could divide the seeds by 4 and plant 25 each week for 4 weeks to extend your blooming season by an additional month. How far you can extend it is determined by your first frost date in the Fall. Check out the map below to see when yours might be. Plan to have you Sunflowers maturity about a week or so before your first frost date so you can still harvest the seeds (if you are leaving the seeds for the animals, then this isn’t as necessary).

US Map showing average first frost dates.

An example of how we might succession plant Sunflower seeds is to take the average first frost in our area, zone 7, which is around Oct 11th and our average last frost date in zone 7, which is about April 30th. Using this information, we can plan to start Sunflowers indoors around the end of March. If we want to plant 100 Sunflowers, we can then look at the first frost date and see that it is about 5.5 months after the last frost date.

If we want to plant a variety that will take about 85 days to maturity, then we know that the last planting must not happen later than about 85 days before Oct 1st or so, to give enough time to harvest the seeds. This means that the last day we’d be able to plant that variety should be July 8th. Divide the time between the end of March and middle of July to figure out when to start your seeds.

Sunflowers, Hydrangea, and Marigolds in a pollinator garden.

Hardening Off Sunflowers Started Indoors

If you start Sunflowers indoors you will need to harden them off before transplanting them outside. The process of hardening off makes sure that the plant doesn’t get “shocked” from the change of climate between your house and the outside. Inside your home, plants have a different humidity, temperature, wind, etc than they would experience outside. By slowly acclimating them to the outside climate you “harden” them to be able to withstand these difference and continue growing appropriately.

Hardening off take place over a week or two by first moving the plant to a porch or under a tree- somewhere that will not get the full force of all the elements. Leave them out in the morning and then bring back inside for the rest of the day. Repeat that for a few days and then gradually keep them out all day moving in to more direct sunlight where you will be transplanting them. Eventually they “harden off” and are able to withstand the elements in their new location and you will have a smooth transplanting experience.

When you are ready to transplant the Sunflowers outside, you just pop them out of the container in to the ground and water in deeply. You can read more information about transplanting Sunflowers in this article here.

Blacberries growing in a rraised garden bed.
Sunflowers transplanted outside after hardening off.
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Activities with Children

Starting Sunflowers indoors is a great activity to do with children! Each child can have a paper towel and some seeds, write their name on the Ziploc bag and let them place the seeds on the paper towels. Let them check daily to see if their seeds have germinated. Older children can even calculate the rate of germination and make a chart with how many days it took each seed to germinate. Another fun activity would be the decorate the containers that you are placing the seedlings in until it is time to transplant the Sunflowers outside.

Photo of bumblebee on Sunflower in suburban garden.

Final Thoughts

Whether you need to start Sunflowers indoors because your growing season isn’t long enough or you just want a head start on your garden, it can be done quickly and easily. Get your seeds together using the Paper Towel method and you will find that growing Sunflowers is an enjoyable, mostly passive, gardening activity. It’s always fun to add new varieties to the garden and the same goes for Sunflowers. With so many options available today, try some new ones each year!

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