Do Sunflowers Kill Your Soil? The Science of Sunflower Allelopathy

Comments · 162

• GA

  @GardeningInCanada · 7 days ago · pinned

  🌱 A little personal ask from me! if you’ve been watching my videos for a while but haven’t subscribed yet, I’d genuinely love to have you here.<br><br>I put a lot of time into researching the science behind these videos because I want this channel to be a place where we don’t just learn what to do in the garden, but actually understand why.<br><br>Every subscription tells me that this kind of science-based gardening content is worth continuing to make and it helps this little community reach more gardeners.<br><br>So if I’ve ever taught you something, made you question an old gardening rule, or helped your garden even a tiny bit, hit subscribe and stick around. It genuinely means more to me than you probably realize. ❤️<br><br>And as always be your own garden scientist. 🌱

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• BR

  @brianb.6282 · 6 days ago

  I shredded some and used it as Mulch around my strawberry plants. Strawberry plants all died and no weeds grew either.

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• PE

  @pepperlie · 4 days ago

  My squirrels make sure I never get sunflower volunteers. They are so cute dragging the flower heads that are twice their size

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• IA

  @iantalmadge · 7 days ago

  Sunflowers are really good soil cleaners, there&apos;s a whole project of them going down a polluted branch of the osabo river in northern Michigan 🌻 thanks for the awesome video Ashley*GIC crew don&apos;t forget to like hype and share Ashley&apos;s hard work with friends and family?🎉🍁🌱🌿🍅🌻🌧️🌞

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• EB

  @eboninkdeathliquidnecrosis · 7 days ago

  Grown Sunflowers every year for a decade. Thought they were just an issue when they are growing. Anywho I live in a swampy hot hell hole so I won&apos;t worry about it.

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• MS

  @MS-de7bb · 3 days ago

  Also after finishing the video 80% I immediately saw an opportunity to suppress some undesirables passively (lazily) and I love that u mentioned it too

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• WE

  @we-simplified · 7 days ago

  I compost mine through my horses. They love the sunflowers and leaves.

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• JM

  @jmac5418 · 1 day ago

  Simply put, you&apos;re AWESOME, Ashley!❤

• CO

  @court2379 · 4 days ago (edited)

  Interesting. Never noticed any effect.

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• DL

  @dlewis9492 · 6 days ago

  Couldn’t figure out why my butterfly pea was not growing in the container that previously had sunflowers. Read an article about this and did a major flush of the soil. It immediately started growing!

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• CO

  @constermonster-if5wy · 7 days ago

  Congrats on your tv spot! I love that dog!

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• FA

  @farmingthedream · 3 days ago

  Genuinely useful video, and you landed the part most people get wrong. Plenty of gardeners assume the growing plant is doing the damage. You correctly put the emphasis on the residue, on accumulation over years, and on chopping at the base instead of digging out a crater. That saves people a lot of pointless work. The warm and moist versus cold and dry distinction holds up too, since the breakdown is driven by soil microbes, so anything that stalls soil biology also stalls the breakdown.<br><br>One pushback, because this is the bit people will carry into next season. The sand versus clay rule runs backwards from the soil chemistry. Sandy soil binds these compounds poorly, so they stay in soil solution and can leach away, but whatever is still sitting there remains fully available to roots. Clay and organic matter bind them, which lowers bioavailability and also keeps them in the bed longer. Neither one is automatically the safe option. Sorption and leaching compete with each other, and which one wins depends on the site.<br><br>The other thing worth adding is scope. The big numbers in the rotation literature come from the Great Plains, where wheat drops around 30 percent and millet around 43 percent after sunflower. Most of that is water. Sunflower roots five to seven feet down and leaves the subsoil dry, and the Akron, Colorado rotation study attributes those yield losses to available soil water at planting. In a semiarid field that effect dominates. Home gardens get irrigated, so what you are actually dealing with is the residue concentration you described, and at bed scale that can be worse, since you are not rotating and you can stack years of biomass in one spot.<br><br>So, the practical version for home gardeners: keep the residue clear of the potato and bean ground, do not build a bed out of pure sunflower compost, and leave the rest alone.<br><br>We grow a lot of sunflowers every year for our cooking oil, and my wife has been doing it basically since she was old enough to sow a seed. They are typically, in the subsistence setting, not really grown in rows. They pop up around the periphery or are interplanted with other plants like field corn or sorghum. Like field corn, they are still suitable for use as trellises for pole beans. We get a large portion of our beans from just putting beans in the ground near sunflowers. So they are a wildly useful plant to have around.<br><br>One thing that is worth mentioning. In Ukraine the stalks get burned, and here in West Virginia we burn those stalks along with black walnut. This destroys the allelopathic compounds and allows us to manage our acid soil. Just something to keep in mind.<br><br>Thanks for an informative video.

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