There's a number of Sosnowsky's hogweed (Heracleum sosnowskyi) plants which have blossomed a while ago and now they are standing with dry seeds ready to be spread by wind. Suppose I gather the seeds (that isn't dangerous when the plant is already dry). There will be perhaps a liter or so of them.

I want the seeds deactivated such that if they fall into soil they definitely give no seedlings ever. Having them destroyed by burning (or throwing into molten steel) would do but that isn't necessary, all I want is to be sure that all the seeds I get through this deactivation procedure give no seedling if they ever fall into soil. So for example burning doesn't look good because how do I ensure that all the volume has burnt fully or at least heated to high enough temperature?

Deactivation procedures should preferably not require complex handling of seeds afterwards. So for example some dangerous chemical wouldn't be optimal because how will I then dispose the contaminated seeds?

Should I boil them? How long would be enough?

Should I soak them in boiled water? Is that enough?

Perhaps some rather safe chemicals would do?

What's an easy, safe and reliable way to have seeds deactivated?

  • 2
    Burning: not so safe: heat will generate up wind, so it makes some of seed to fly away. Usually I prefer to remove flower before they blossom, but now I would put in water for few weeks and let them rot Sep 26, 2017 at 15:04
  • Perhaps add a little sugar to water so as to encourage bacterial/fungal growth. Sep 27, 2017 at 14:37
  • A little confused why you are so intent on doing this. Stormy (in answer below) is right: gathering and then destroying seeds is not going to stop your weeds growing. Surely you have missed quite a few seeds which are now on the ground ready to perpetuate your weed population. Since you have collected so many of these seeds though, can't you just put them with the rest of your trash for transport to the dump/landfill?... Or are these weeds so noxious that you are trying to prevent their spread into the rest of the planet? Sorry if the "why" isn't necessary to answer your Q., but it puzzles me.
    – Lorel C.
    Sep 28, 2017 at 14:51
  • @LorelC. Have you ever lived in a region where Sosnowsky's hogweed is common?
    – sharptooth
    Sep 28, 2017 at 15:01
  • No, that's probably why I don't understand why you need to de-activate the seeds; can you explain? I'm curious.
    – Lorel C.
    Sep 28, 2017 at 15:38

3 Answers 3


Easy as can be. Seeds are not some magical movie monster that cannot be killed.

Put them in a pan, bake at 250°F / 120°C (or higher, but that should be adequate) for an hour, they should be good and dead.

Or - wrap in aluminum foil, place in fire, cover with coals (if you don't want them in your oven/house) You could also do the foil wrap and then put them in your oven if merely containing them will keep you happy.

  • And old biscuit tin or similar works well if it's not painted or plastic coated. Even a terracotta pot and saucer should be OK if not waterlogged and not heated too fast
    – Chris H
    Sep 27, 2017 at 15:02

You could always just dig a hole and throw them all in (and bury them). Seeds planted too deeply are known not to sprout above the soil, if at all. If it's Morning Glory, you might consider another option.

Another alternative is throwing them in the trash.

If you can't get rid of them and don't want to dig a hole (or bake/boil/burn them), you can always put them all in the same spot (so you'll only have weeds in a tiny area).

Don't forget that some birds eat weed seeds (the seeds aren't all bad); I'm not sure about your particular kind of weed.


Oh shoot. If you are looking at dried seeds it is way too late to do anything at all about deactivating those seed. Sorrryyy. The best time to stop weeds is before the plant is able to flower or shortly after the seeds germinate. Baby plants easily killed.

This plant is a biennial...yes? So easy to eradicate by 'weed wacking' using a line trimmer on less than the highest rotation...talk about that later. Or using a hula hoe. Or using a chunk of tarp and scooting around on the surface smooshing baby weeds. Get the chunk of tarp fitted with slots so you can secure the tarp to your feet just enough to hold. Change foot slots and scoot around some more.

Trust me, I'd do this at night where no one can watch!

If there are areas such as gravel driveways or paths, you can use garden strength vinegar, I think it is called 'weed block'...changes the pH to ACID where no plants can germinate much less grow. Nothing grows. To make the soil usable again you lime it and bring the pH back up.

  • 1
    Yeah, cool, but I still want to gather seeds that are easy to gather and somehow deactivate them. That's what the question was about.
    – sharptooth
    Sep 27, 2017 at 8:55
  • Well, baking them, burning them, burying them deeply would all work. You've got lots of seeds already removed and seeded in your soil and beyond. That is where I was going. Gotta get to plants you don't want to seed before they flower to be effective.
    – stormy
    Sep 27, 2017 at 20:31
  • Yes, I know that some seeds are already in the soil, that's another problem.
    – sharptooth
    Sep 28, 2017 at 10:42

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