Harvesting castor bean seeds from your garden is easy. In this post, I’ll give you step-by-step instructions for how to collect castor bean seeds from your plants, and I’ll also show you how to store castor seeds.
In some areas of the world, castor bean plants are invasive. But here in Minnesota, they make beautiful and unique tropical plants that die back every fall (funny how that works).
I love growing castor bean plants in my tropical garden, and I always get tons of compliments on them!
I especially love this red castor bean variety that I have been growing in my tropical garden for a few years now.
Castor Bean Seeds Harvesting
I first received my red castor bean seeds in a trade, and have been collecting the seeds from my garden every year since. It’s very easy to collect castor plant seeds and save them for planting next year.
Castor bean flowers are insignificant, but they form gorgeous seed pods that look like flower puffs at first.
Red castor bean seed pods start out as bright red puff balls, which really add to the beauty of this plant.
The seeds will form inside of these red puff balls, so be sure to leave them on the plant if you want to collect castor bean seeds.
When To Harvest Castor Bean Seeds
The seed pods will start to fade and eventually turn brown. Allow castor bean pods to dry on the plant so that the seeds have plenty of time to mature.
Eventually, the seed pods will split open, which is a sure sign that it’s time to start collecting castor seeds.
Don’t worry about collecting castor bean seeds before frost, I usually don’t get around to it until after a hard freeze, and I haven’t had problems with seed viability.
What Does A Castor Bean Seed Look Like
Castor bean seeds are oval shaped and have a nub on one end of the seed. They are pretty large, and hard to miss – larger and rounder than edible bean seeds.
Truth be told, castor seeds actually kinda remind me of an engorged wood tick (disgusting, I know!).
How To Collect Castor Bean Seeds
To collect castor bean seeds, first clip the dried seed pods from the plant. Castor seed pods are very prickly, I recommend using gloves to handle them.
You can store the seeds right in the pod, or remove the seeds from the pods before storing them.
To collect castor plant seeds, break open the seed pods. There are three castor seeds per seed pod. Sometimes not all the seeds in the pod are large enough to keep.
Discard any castor bean pods or seeds that are small, they won’t be mature enough to germinate.
How To Store Castor Bean Seeds
Allow your castor seeds to dry completely before storing the seeds. Ideally, the seeds should be stored in a dark, dry place until spring.
Once they’re dry, you can store your seeds in a paper bag or small plastic containers (like these film canisters).
If you wan to share them with friends, then these small envelopes are perfect, or you can get customized seed envelopes, or make your own DIY seed envelopes.
I store my seed collection in a plastic shoe box, but if you like to organize yours, then a Seed Keeper would be perfect!
It’s important to note that all parts of the castor bean plant are poisonous, so be sure to keep castor bean seeds and seed pods out of reach of children and pets at all times.
How Long Does It Take To Harvest Castor Beans?
You may need to wait as long as 170 days for your castor plants to become fully mature before you can harvest the seeds.
They need a long, hot growing season. So if you live in a cold climate like I do, make sure you give them plenty of sun.
Collecting castor bean seeds from the garden is fun and easy! It’s a great way to grow your favorite plant year after year, and share the seeds with friends (just be sure to let them know that both the seeds and plants are poisonous).
Now that you know how to collect castor bean seeds, learn how to grow castor seeds next!
If you’re tired of struggling, and want to learn how to grow any plant you want from seed, then enroll in my online Seed Starting Course. It’s a wonderful, fun, self-paced course that will teach you everything you need to know to easily grow your own seedlings. Enroll and get started today!
Or, if you just need a refresher, then my Starting Seeds Indoors eBook is for you! It’s a quick-start guide that will get you planting seeds in no time.
More Posts About Saving Seeds
- Collecting & Sowing Spider Plant Seeds
- How To Harvest & Collect Seeds From Your Garden
- How To Collect Lavender Seeds From Your Garden
- How To Harvest Butterfly Weed Seeds
Share your tips for how to collect castor bean seeds in the comments section below.
Ken says
Amy, you are incorrect stating that freezing weather will kill castor bean seeds. I’ve kept mine in the freezer for over 10 years and they grow just fine.
Amy Andrychowicz says
Interesting. It must have to get below a certain temperature to kill castor seeds, because they definitely don’t survive the winter outside here in MN – but it can get down to -20F+ below zero, which is much colder than a freezer. Thanks for sharing your experience!
Shirley says
My plant This year has like a flower or more like a mushy cauliflower growing underneath the sea pods why is this ? did some of the pods turned to dust ? The rest of the pods are bright red nowhere near ready to come off the plant yet.
Amy Andrychowicz says
It sounds to me like the flowers weren’t pollinated on your castor plant, and that’s why no seeds formed and the pods turned to mush. I would just prune it off.
Joey Phillips says
What if they self sow but don’t pop up until you’ve got the rest of the garden.thriving and growinng well, I’ve got a couple that’s sprouted up right in with my watermelons will this poison. What’s around.the caster bean plant?
Amy Andrychowicz says
No, the poison doesn’t leach into the soil, and is not absorbed by other plants. However, they do grow very large, and will compete with your veggies for water and light. So, if I were you, I would move the castor bean seedlings somewhere else so they have plenty of room to grow, and won’t crowd out your vegetables.
Jodi says
Hi Amy. I’m also in Minnesota. I purchased some castor seeds to plant. Do you just put them in the ground, or do you need to start them inside first? I read that they need a lot of heat to germinate. Thanks!
Amy Andrychowicz says
Since our growing season is so short here in MN, and the ground is so cold in spring, it’s best to start castor seeds indoors. Here’s how to do it step by step for the best results.
Brenda says
Hi Amy. I picked the prickly balls off the plant on the fall. Now when I get the seed out, the seed doesn’t feel really hard. Should the seed be hard?
Amy Andrychowicz says
Castor seeds should be pretty hard after harvesting them, if you did it at the right time. The prickly balls (seed pods) should be brown, dried out and brittle before collecting the seeds. If the seed pods are still red or soft, the seeds probably aren’t mature enough to be viable. I would either plant some to see if they grow, or perform a viability test on them.
Rodger Stevens says
Hello Amy, I grew some castor plants at one end of my vegetable garden and collected some seeds when they were ready, but I didn’t collect them all. Will my vegetable garden be safe when I start working the soil for the next planting season ?
Amy Andrychowicz says
If you live somewhere cold, the freezing weather will kill the remaining castor seeds, so you won’t have to worry about them reseeding. But, if you live in a warm climate, then I would remove them or they could self sow.
shashere michael says
hi, actually I don’t really know much about castor beans, but a friend of mine enlightened me of it. I do see it all the time, it grows and become a tree in my area.
how can the oil be produce?
Amy Andrychowicz says
Castor oil is pressed from the seeds. I’m not sure if this is something you’d be able to do at home or not, I’ve never tried it myself.
Linda says
How do I dispose of the castor bean plant at the end of the year. If I put it in my garbage it will go to the landfill. Is that ok since the plant and seeds are so poisonous?
Amy Andrychowicz says
I put my castor bean plant into my compost bin, or into the yard waste bin for composting.
Angela Holt says
If its poisonous is it a good idea for a compost ben? Expecially if your compost is being put on a vegetable garden….seems like it wouldn’t be ideal.
Amy Andrychowicz says
The castor bean poison doesn’t survive composting. So, it will be gone once the plant is done decomposing.
Michelle says
Thank you everyone for tips on growing caster beans. This is my 1st year. I was late in starting. My plant is about ankle high but I am proud of him. I look forward to all the garden advise. I am in Oklahoma
Amy Andrychowicz says
You’re welcome!
Linda says
I grew a giant castor bean plant from seeds I bought on line. It grew to well over 15’ and was beautiful. We had a bad wind and rain storm which blew it over – breaking the stalk. The blossoms are still red. Will I still be able to gather seeds from it? How should I get rid of it? It’s laying on the grass now.
Amy Andrychowicz says
If your castor bean seed pods are still red, then the seeds may not be mature enough to grow. There may still be enough energy in the plant for the seeds to mature though. I would just allow the plant to dry out, and once the seed pods turn brown try harvesting them. It sure doesn’t hurt to try. 🙂
Maggie Morish says
Good job in sharing this. I’ve always wanted to grow these plants but decided not to after finding out that they’re poisonous. From what I’ve read, one castor bean is enough to kill an adult in minutes. Which brings me to this question — what precautionary measures do you take to make sure that no kids or animals get their hands on them?
Thanks in advance Amy!
Amy Andrychowicz says
I grow my castor bean plants in a fenced in backyard, and we don’t have any pets or kids to worry about. 🙂 When I harvest the seeds and bring them inside (we do have house cats), I put the into a container that has a lid and put them up on a high shelf in a closet that they can’t get to.
Debbie says
I have been growing these beauties for several years, my father in law got me hooked! I have grown some big ones while leaving the pods on till the end. I live near Niagara Falls and have seen them in the parks by the falls and they gotta be 30 to 40 feet tall and probably the same in diameter. Because they are in the public park all of the flowers are removed so all the growing energy goes to leaves and stalk. Both the stalks and leaves are huge! Stunning!!!!
Amy Andrychowicz says
Yes, some varieties of castor plants can grow very large! They are so gorgeous.
Kelly Hall says
I live in Tulsa OK and have some castor bean plants this year that are 20-25 feet tall! I’m going to try to post pic. We’re having a hard freeze tonight and seeds are green. So glad to find this site saying not to harvest yet. I would LOVE to have some red castor bean seeds if anyone would be willing to trade for my giants. Please let me know. Thanks again for the great advice!
Amy Andrychowicz says
WOW! Those are some tall castor plants! So cool! You can’t post photos here, but you can on my Facebook page or tag me on Instagram. Would love to see them!
Jim Zwolinski says
We live near the bottom of Lake Huron not too far from the shore. I remember my mom planted giant castor beans 50 years ago and how impressive they were. This season Teri my wife planted 2 in one of the circular gardens she build in the middle of our side yard. It was quite enjoyable to watch them grow to their present 10 foot height. One has a volley ball size cluster of seed pods. Yea babe. I told Teri I was going to plant a Castor Bean forest next year. She shot me down on that but you know what? Try to stop me. Once I get it all going our respect for life will preclude her terminating my project. She already taught me to germinate the seeds and get the seedlings going before planting. Silly girl. A heartfull of thanks is the best prayer. How can one not be thankful amid the splendor of Creation and help from famil and friends?
Amy Andrychowicz says
LOL! It sounds like you are hooked on growing castor bean plants! They are gorgeous, so I can’t blame you. 🙂
Peggy shallcross says
I grew them in DE this summer. They are beautiful, 10 ft tall. But the pods never went to flower (yet, it’s October) . Maybe they got started to late, but I’m still going to try harvesting seeds. Love the plant, so tropical looking.
Amy Andrychowicz says
Castor bean seed pods won’t flower, the flowers come before the pods. The flowers are insignificant so you probably never even noticed them, LOL! But if you have seed pods, then you should be able to collect the seeds. I love it too, so pretty!
Caren Bailey says
This was mine and my husbands first year growing the castor bean. I’m really impressed with the plant, however one plant seems to be shorter and staulker than the others with darker green leaves. We ordered the seed from a seed company and thought maybe seeds got mixed. I was interested in saving the seed and planting again next spring. After reading all the information everyone has provided I think I now know what to do. Thank you, Caren
Amy Andrychowicz says
Yes, it sounds like the seeds got mixed up and you grew two different varieties of castor bean. 🙂 Glad you found the steps for collecting castor bean seeds helpful! Awesome.