How to Grow Sunflower Microgreens: Complete Step-by-Step Guide

11 de junio de 2026

Sunflower microgreens are one of our all-time favorites to grow and eat. They are nutty, crunchy, and substantial enough to stand in for lettuce on a sandwich, and they show up on just about everything in our kitchen, from tacos and pizza to peanut butter and jelly sandwiches, and even dipped in dark chocolate. After 7+ years of growing them, we have changed how we do it more than once, and this guide reflects exactly how we grow sunflower microgreens today.

The biggest change is that we no longer soak our seeds. We used to pre-soak every batch, but after running our own germination trials we switched to a no-soak method that has been faster and just as reliable in our space. We will walk through that below, along with everything else you need to go from seed to harvest.

How Do You Grow Sunflower Microgreens?

Sunflower microgreens are grown from black oil sunflower seed in a shallow tray, kept under weight in the dark to germinate, then moved into light to green up before harvest. Here is the short version of our current method:

Rinse and seed: Rinse the debris off about 125 grams of black oil sunflower seed, then spread it evenly across a 10x20 tray filled with your medium of choice (reusable silicone, coco coir, or soil). No pre-soak needed.
Water and cover: Mist well, then cover with a tray and a heavy weight (we use a 15 pound paver) in a dark spot.
Germinate: Keep covered and dark for roughly 4 days, misting once or twice a day so the surface does not dry out.
Blackout and light: Flip the top tray into a blackout dome for about a day, then move to light and start bottom watering.
Harvest: Cut with a sharp knife around day 8 to 10, once the cotyledons are full and before the first true leaf takes over.

That is the whole arc. Sunflower can be a little finicky compared to fast brassicas like broccoli or radish, but the steps below make it very repeatable. If you are brand new to all of this, start with our complete guide to growing microgreens first, then come back here for the sunflower specifics.

Why We Love Growing Sunflower Microgreens

Sunflower is a large-seed, heavy-yielding crop, which means it produces a lot of biomass per tray. In our grows a single 10x20 tray runs roughly 1 to 1.3 pounds (about 490 to 615 grams) depending on the seed batch and method. That is a real harvest from one tray.

The flavor is the other reason we keep it in rotation. Sunflower microgreens are mild, nutty, and crunchy, with thick stems and big cotyledons that hold up to texture-forward dishes. We have even noticed that trays with more red stem coming through tend to taste a touch nuttier. They pair well with milder greens and add bulk that more delicate varieties cannot. For more ways to put them to work, see our roundup of the many ways you can use microgreens.

A dense, harvest-ready tray of sunflower microgreens held up to show the full canopy and seed coats

What You'll Need to Grow Sunflower Microgreens

Here is the short supply list we use for a standard 10x20 grow:

Black oil sunflower seed. This is the variety grown for microgreens. We buy ours from True Leaf Market. Plan on about 125 grams per 10x20 tray.
Three trays. A no-hole bottom tray for the water reservoir, a holed (mesh) tray that holds your medium and seed, and a second no-hole tray on top to trap humidity and later flip into a blackout dome. We use Bootstrap Farmer 10x20 shallow trays.
A growing medium. We have grown great sunflower on both coco coir and our reusable silicone grow medium. More on choosing below.
A heavy weight. Sunflower likes more weight than smaller crops. We use a 15 pound paver during germination.
Water and a sprayer. A mist setting for early days, plus a way to bottom water once roots come through.
Optional hydrogen peroxide. We like to lightly mist with a food-grade hydrogen peroxide and water mix (roughly 2 tablespoons of 3% per liter) since sunflower seeds can decay and mold after they get wet. This step is optional.
A sharp knife and a scale. A very sharp harvest knife makes clean cuts, and a scale lets you track yields. See our breakdown of what works best for harvesting microgreens.
Fertilizer (optional). When we bottom water on coco or silicone we use Ocean Solution 2-0-3 at 0.5 oz per gallon, pH balanced to 5.5 to 6.0.

Should You Soak Sunflower Seeds for Microgreens?

This is the most common sunflower question we get, and our answer has changed over the years. Soaking is optional. We no longer do it, but it is still a valid method, so here is the full picture so you can decide for yourself.

Why Some Growers Soak

Black oil sunflower is a large, hard seed, and soaking is the traditional way to wake it up. The idea is that a pre-soak jump-starts germination and softens the seed coats so they release more easily later. Sunflower is also known for being slower to germinate than small brassica seeds, so a soak has long been the go-to for evening that out. That reasoning is sound, and it is why you will see most older tutorials, including some of our own, soak first.

How to Soak Sunflower Seeds (If You Want To)

If you prefer to soak, here is the method we used for years:

Measure your seed (about 125 grams for a 10x20) and rinse it well, since sunflower seed tends to be dirty.
Add the seed to a container with enough water to cover it. You do not need much. For 125 grams we filled to roughly the 1.5 liter mark.
pH balance the soak water down to the 5.5 to 6.0 range. Our tap runs around 8.0, and we feel we get better germination bringing it down. Add pH-down a few drops at a time and check as you go, since it is easy to overshoot.
Set something on top of the seed to keep it fully submerged so nothing floats.
Soak for about 8 hours, then rinse again before planting.

A note on soak time: in our own testing, anywhere between 1 and 8 hours gave us good germination. Past the 8 hour mark we started seeing weaker germination and faster seed decay, which led to more mold. We also skip seed sanitizing at this stage, though some growers do it. We only pH balance.

Why We Switched to No-Soak

A few years back we ran a side-by-side germination trial comparing soaked seed against no-soak seed using the same variety, medium, and tray setup. In our controlled space, the no-soak tray did not just keep pace, it came out ahead. Our soaked tray finished at 520 grams and our no-soak tray at 615 grams, a 95 gram difference in favor of no-soak, with better root structure and a slight height edge too. The flavor tasted identical. We also saw fewer seed coats clinging on and less decay, so we were not spot-treating for mold the way we used to.

One thing that experiment made clear: how you seed matters more than whether you soak. The trays where we buried seed under a layer of medium fell behind, pushed up a messy shelf of coco, held on to more seed coats, and grew unevenly. Seeding directly on top of the medium won every time. Since that test, we rinse the debris off our seed, skip the soak, and seed right on top. We always encourage you to run your own trial though, because every seed batch behaves a little differently. For the why-behind-the-weight, our experiment on why microgreens need weight during germination is a good companion read.

How to Grow Sunflower Microgreens Step by Step

Step 1: Set Up Your Three Trays

Stack a no-hole tray on the bottom as your reservoir. Set a holed mesh tray inside it to hold your medium and seed. Keep a second no-hole tray aside for now. It will sit on top to trap humidity during germination, then flip into a blackout dome later.

Step 2: Rinse and Seed the Tray

Fill your tray with your medium of choice (reusable silicone, coco coir, or soil) and give it a light mist so seeds make contact. Rinse the debris off your 125 grams of black oil sunflower seed, then spread it evenly across the surface. Because the seeds are large, full coverage with seeds nearly touching is good, but break up any thick clumps. Clumped, stacked seed is where disease and uneven germination tend to start. The nice thing about a big seed like sunflower is you can go back and nudge clusters apart by hand without any trouble.

Macro of black oil sunflower seeds germinating with white radicles emerging

Step 3: Water and Add the Weighted Blackout

Water the tray well without pooling water on the surface. This is the point where we like to add the optional light hydrogen peroxide mist, since sunflower seed decays faster than most after it gets wet. Place your second no-hole tray on top, then set your 15 pound paver on top of that, and move the whole stack to a dark shelf. The weight encourages an even canopy and strong, anchored stems.

Step 4: Germinate in the Dark

For roughly the first 4 days, keep the tray covered, weighted, and dark. Check it morning and evening, misting lightly if the surface looks dry. You will see radicles (the first root tips) push through the seed, then white roots start reaching for the bottom tray. As soon as you see roots underneath, you can start lightly misting the bottom tray to keep those roots white instead of letting them brown.

Step 5: Flip Into Blackout

Once the seedlings have lifted the top tray and stems are standing up, flip that top tray into a blackout dome (open side down, lifted off the canopy) for about a day. This stretches the stems and helps the plants stand tall before they see light. If you are still seeing a lot of seed coats, an extra day under blackout often helps. For more on this timing, see our guide on when to switch from weight to blackout.

Step 6: Move to Light and Start Bottom Watering

Now move the tray under your grow lights and stop top watering. Pour water directly into the bottom reservoir tray instead. We bottom water with about a cup at a time, once or twice a day, using our Ocean Solution mix pH balanced to 5.5 to 6.0. If stems start falling over or roots begin browning, that is your cue to water a little more. For everything on watering volumes and schedule, our complete watering guide covers it in depth.

For lighting we run a 16 to 17 hour daily schedule with T5 LED lights about 8 to 12 inches above the canopy. We run three 20 watt T5 lights per shelf and have used the same setup for years. You can see the full breakdown in our microgreen lighting guide.

Sunflower microgreens with thick white roots growing through a mesh tray under grow lights

Step 7: Knock Off the Seed Coats

Sunflower seed coats (also called seed hulls or seed holes) are the husks that cling to the cotyledons. Misting the canopy softens them, and once the tray is in light you can gently rub a clean hand back and forth across the top to loosen and pop them off. Wash your hands first, go light so you do not snap stems, and switch directions as you go. Repeat this once or twice a day until harvest. A longer time under weight and blackout also reduces how many seed coats you have to deal with in the first place.

Sunflower microgreens shedding their black hulls as yellow cotyledons emerge over a mesh tray

Step 8: Harvest

We harvest sunflower around day 8 to 10, once the cotyledons are full and before the first true leaf starts emerging between them, since that is when the flavor begins to turn bitter. Use a very sharp knife and let it glide through rather than sawing, which protects shelf life. Cut about an inch to an inch and a half up so you do not pull medium into your product or nick a reusable silicone grow medium, and pick out any stray seed coats in the canopy as you go. We do not wash before storing, since damp greens in a bag shorten shelf life. Rinse right before eating instead.

Harvesting sunflower microgreens by hand in the On The Grow space

A fresh handful of harvested sunflower microgreens held up in the On The Grow space

Best Growing Medium for Sunflower Microgreens

Sunflower grows on all three of our usual mediums, and we have documented it on each. The two we reach for most are coco coir and our reusable silicone grow medium.

Coco coir. Single use, forgiving, and a reliable performer for sunflower, especially when temperatures dip. We no longer sell coco coir, so we link the coco coir we use on Amazon. After harvest we compost the spent coir rather than reusing it.
Reusable silicone grow medium. Sunflower works on both our 1.2mm standard and the 1.7mm large hole version. The silicone is reusable for many grow cycles and rinses clean, which is handy with a debris-prone seed like sunflower. See which seeds work on it in our reusable grow medium seed compatibility guide, and our full silicone medium overview.

We put these two head to head on sunflower specifically in our coco coir vs. reusable grow medium sunflower case study, which is worth a read if you are deciding between them. If you want a broader ranking, see our overview of the best hydroponic grow mediums for microgreens.

Common Sunflower Microgreen Problems

Sunflower is rewarding, but it is also the crop most likely to test your patience. The most common issues we see:

Stubborn seed coats. Usually means the tray needed more time under weight or blackout. Increase weight time on your next grow and keep misting and brushing the canopy.
Mold and decay. Sunflower seed decays faster than most after getting wet. Even, non-clumped seeding, good airflow, and that optional hydrogen peroxide mist all help. Our complete guide to microgreens and mold covers how to tell mold from harmless root hairs.
Uneven or short cotyledons. Seed batch matters a lot with sunflower. We once started a new seed lot and got noticeably smaller cotyledons than our previous batch, even with the same method. A finicky tray often just needs a tweak to weight or blackout time on the next round.
Messy, buried growth. Seed directly on top of the medium, not under a layer of it. Burying sunflower seed pushes up a shelf of medium, traps more seed coats, and grows unevenly.
Leggy, falling-over stems. Usually a lighting or watering issue once in the light phase. Lower your lights and check that the reservoir is not running dry.

Two trays of early sunflower microgreens germinating with seed coats still attached

For a wider net, our roundup of top microgreen growing mistakes catches most of what trips up newer growers.

What to Do With the Leftover Medium and Roots

After harvest you are left with a dense mat of roots, medium, and leftover seed. On coco coir we peel that whole mat up and toss it in our compost pile, then use it later in our outdoor garden. We never bring used coco coir back into the grow space, since that is a path for pathogens into your next crop. On a reusable silicone grow medium, we slide the root mat off, pick off anything stuck on, then wash with hot soapy water and sanitize so it is ready for the next batch.

Those leftovers are useful beyond the compost pile too. Growers we know put them in worm bins, feed them to rabbits and other livestock, or even trade them to local egg dealers, since chickens love microgreen leftovers. For the full rundown, see what to do with used grow medium after harvest, and our guide on how to clean and sanitize trays and reusable mediums.

Are Sunflower Microgreens Good for You?

Sunflower microgreens are a satisfying, nutrient-dense green. Research has associated sunflower with vitamin E, healthy fats, magnesium, copper, and selenium. More broadly, the landmark 2012 study from the University of Maryland and USDA found that many microgreen varieties contained 4 to 40 times more nutrients than their mature counterparts. You can read the University of Maryland summary of the research here.

As with any microgreen, the quality starts with clean, high-quality seed and good growing practices. Penn State Extension's ABCs of Microgreens is a solid production reference on that front.

How to Eat Sunflower Microgreens

Sunflower's mild, nutty flavor and crunch make it one of the most versatile microgreens to actually eat every day. A few of our favorites:

Piled on tacos, pizza, and sandwiches in place of lettuce
Tossed into salads and grain bowls for texture
Blended into smoothies or added to fresh juices
As a finishing garnish on soups, added at the table, not cooked in
On peanut butter and jelly sandwiches, or on toasted homemade bread with apricot jam

Always add microgreens fresh at the end rather than cooking them, and rinse right before eating. For 25+ everyday ideas, see how to eat microgreens.

Fresh sunflower microgreens piled on homemade bread with apricot jam from On The Grow

Frequently Asked Questions About Sunflower Microgreens

How long do sunflower microgreens take to grow?

In our space, sunflower microgreens are ready to harvest in about 8 to 10 days from seeding. That includes roughly 4 days of weighted germination, about a day of blackout, then a few days in light before harvest. If you are using older seed, expect slower germination and growth times.

Do you have to soak sunflower seeds before growing microgreens?

No. Soaking is the traditional method, but after our own germination trials we switched to a no-soak method and have had excellent results. If you prefer to soak, rinse first, soak about 8 hours in pH balanced water with the seeds weighted down, then rinse again before planting. Either way, always rinse the debris off your seed first, since sunflower seed tends to be dirty.

Why do my sunflower microgreens still have seed coats stuck on?

Clinging seed coats usually mean the tray needed more time under weight, and could have maybe benefited from better watering during germination. Misting the canopy and gently brushing it with a clean hand once in light helps pop them off. Increasing weight time on your next grow reduces them too.

Can you grow sunflower microgreens without soil?

Yes. We grow sunflower on coco coir and on our reusable silicone grow medium, and you can also grow it hydroponically. Sunflower works on both the 1.2mm and 1.7mm silicone, so soil is not required.

Do sunflower microgreens regrow after you cut them?

No. Unlike peas, which can sometimes give a smaller second harvest, sunflower microgreens are a single-harvest crop. Once cut, compost the medium or clean your reusable medium and start a fresh tray.

How much do sunflower microgreens yield per tray?

In our 10x20 grows, sunflower has run roughly 1 to 1.3 pounds (about 490 to 615 grams) per tray, depending on seed batch and method. It is one of the heaviest-yielding microgreens we grow.

Ready to Grow Your Own Sunflower Microgreens?

Sunflower is well worth the slightly steeper learning curve. Once you dial in your weight and blackout timing for your seed and space, it becomes one of the most satisfying crops you can grow at home. If you are just getting started, our 7x14 OTG Microgreen Tray Kit is a beginner-friendly way to grow your first trays, and the free tray-specific seeding guide gives you exact rates by tray size.

Want the full A to Z, every crop and method in one place? Our Microgreen Masterclass walks through it all, and you can browse more tutorials any time in our video library.

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The results and opinions shared in this post are based on our own first-hand testing in our specific, controlled grow space. Any mention of a brand or product reflects our own experience, not a sponsored or definitive review. Your climate, water, seed, and setup are different from ours, so your results can vary. We always encourage you to run your own experiments and see what works best for you.

The information in this blog is for educational purposes only and is not intended as medical or nutritional advice. Always consult a qualified healthcare provider for personal health guidance.

— On The Grow®, LLC

Happy growing!