Mammoth Sunflowers

[zanthal]

Hi,

That big green smiley face for the topic icon indicates that I'm a happy green noobie to growing anything from a seed.

I followed some instructions from another website on sprouting these Mammoth variety Sunflower seeds I have.

They said to put 4 seeds about an inch below the soil of prepared ground.

The ground in my backyard is hard and clumpy and is going to need to be tilled and have good soil added to it in order to be suitable as a host for these, so I've got them in four inch pots right now.

After two days of light watering in about the fullest day long direct sunlight you can get, I dug up the seeds and found that every one of them has at least the beginnings of a sprout breaking out of the seed shell.

These are big flowers, as far as I'm aware, these are the biggest flowers there are, or at least I believe I've ever seen.

So my question after this long story here is, are these four sprouts in each pot going to need to be separated to keep from too much competition for soil and sunlight? Do I want to separate them?

I know that they need to be a good 1-2 feet apart in order for their roots to have room, but I'm wondering why would a gardening instructional website want you to sprout 4 seeds in the same location if they couldn't handle growing together that close?

If anyone happens to know, how deep do their roots grow, so I know how deep to till the soil in which they will finally planted?

Ah yes another question ... these are annual flowers, which I've learned means they are going to die before next spring (right?). They take 75 days to bloom, I'm wondering, do they die because of the winter cold or lack of sunlight between seasons, or do they have an actual lifespan limitation? I'm starting them late in the season but I'm in sunny California and 75 days will put them in the middle of October and we usually have decent sunny weather that isn't very cold still at about that time of year.


Thanks

P.S. - I'm a sponge for extra information like dry soil here, so if you've got tips or anything else you think I should know about caring for these gigantic blooms, I'd appreciate it all.

Post POST script - This will probably sound crazy to do or at least not recommended ... but if you were going to grow one of these 12 foot Mammoth Sunflowers in a pot, how big of a pot would it need to be? I'm suspecting 18 inches wide, easy

[evtubbergh]

To answer some of that for you;

Sunflowers don't like to be moved so now that they are in pots be very careful with their roots when you move them and do it asap.

Yes, they need to be separated although if they already have more than one root or root hairs that may be difficult. In future sow them separately directly in to the ground. If you have more than one plant in a spot you would usually cull the smallest and leave only biggest one.

Do you have any more seeds?

Annual means they have a specific lifespan. Sunflowers produce a large quantity of seed then die releasing their seed, which can grow next season. Even so, some plants would last longer if it were not for the cold you guys get and then they are also annuals.

[applestar]

I experimented with growing sunflowers and my conclusion is that pre-germinating, then sowing one in each spot 12" apart is the best way. (Thin to 24" - 36" apart for maximum growth later) You could do the same with the ones that have pre-germinated in the pots if you do it right now,

4 in each spot is to hedge your bets because not all seeds germinate and sometimes germination % can be low. But it shouldn't be read as "each hole". Also 4 inch pot is too small. By the time they sprout with a loop above the soil, the single seed root will be 3" long. By the time those seed leaves open up, the roots will be 4-5" with root hairs. A 4" pot not completely filled to the top, and seeds sown at least 1/2" below -- get the picture?

Sunflower roots and sprout are brittle and difficult to handle to transplant.

Look in this thread for additional info.

Subject: 2014 pre-germinating/sprouting experiment Peas, Corn, Curcs

Did I mention I'm trying sunflowers and beets now? Started soaking them two nights ago and after full day of rinse and drain, the sunflower seeds have already started to germinate.... I already knew it works for sunflowers after last year's experiment, but I had a couple of sunflower seed heads hanging upside down on the end of a curtain rod all this time (completely forgot about them) and I had no idea if they were still viable after being near the window and all.

BTW -- I've only ever started them in spring, and earlier in spring at that. Sunflowers can be sown as early as corn. But I think they do like to start out in cooler temps. I don't know how well the seedlings grow in the heat of the summer or even sprout, ordinarily. Your starting them presumably indoors in the pots may have helped with the germination.

Sunflowers are attacked by any number of sucking insects (and slugs as seedlings) but once they get going, they can generally shrug those off and keep growing in spite of them. Most likely, the summer pest pressure would be difficult for seedlings and you will need to give them extra care and attention.

[applestar]

If they need 24" spacing then logically they need 24" diameter container. But even then the containers would be WAY too shallow. I think their height will be stunted.

I can't see these growing in any kind of containers:

Subject: Here's my new sunflower& "house"

Update photo. The two sentinels have flowered!


The bamboo pole, placed next to the taller one for reference, is 8 ft long.

[rainbowgardener]

I did try growing a smaller variety of sunflower (not the mammoths) in a large-ish container one time. Container was about 5 gallon bucket size. Plant did well at first (it was started indoors and then transplanted into the pot), but the bigger it got, the more obviously it was stunted from the size it should have been. It bloomed (one flower), but before it could set seed, it got a bad case of powdery mildew and died. Not saying that would always happen, but I do think it was probably more vulnerable to disease trying to grow in the pot. It was also not in full, all day sun, since I have very limited areas like that in my yard.

[zanthal]

These responses are great, thanks.

And those 12 footers, applestar, once the seeds start to grow in will cause the bloom to face downward under it's own weight, right?

[applestar]

Yep. I don't think I have a picture, but they drooped down to the point that I could reach up and rub the spent flowers off the seeds. If I remember correctly, a squirrel jumped up on one of them and the extra weight broke it off -- fortunately after the seeds were mostly mature. Luckily, I was home and immediately harvested them both

After processing -- removing the outer calyces and any seeds with holes, chasing down grubs, etc. before hanging the rest of the uninfested heads to dry. I tossed the bug eaten ones to the squirrels

...They did get treated to the good ones later on in the depth of the winter when I feed the birds.

[zanthal]

It had to have been the same squirrel from Ice Age.



This is a long shot that anyone will actually have any experience with this ... but you guys know your stuff, you will probably have good advice anyway:

I have some Russell Lupine (perennial) seeds in the fridge "scarifying" ... do I need to be concerned about these two plants not getting along or having their differences of opinion kept underground with their roots trying to harm one and other?

[zanthal]

It's time to consider harvesting the seeds from my Mammoth Sunflowers

I have a few questions that didn't quite get answered everywhere else I read about harvesting these giants.

Do you remove the head of the plant as soon as the face of the flower is drooping downward, facing the ground? or do you want to wait until it has begun to brown as well?

If we want to do a lot of the drying while the plant is still in one piece, does it all require watering since we are wanting it to dry out?

I'm in California and we are in severe drought, if I can stop watering these thirsty guys, I want to.

Right now they are both drooped and facing the ground, but the only signs of dryness are on the yellow petals, everything else is green and looking good.


Thanks

[applestar]

It's only 10:20 but I'm so sleepy! Sorry for the hurried response

Here are links to previous posts.
Subject: Sunflower is blooming!

The first to open large flower head and an couple of the next to open lateral heads of the tall super multi-headed sunflower from the OP (8-9 feet tall) and the single large headed short sunflower next to it (only about 6 feet tall) were ready to harvest today, so I took a last photo before beheading them.

Subject: harvest sunflower ?

I remember posting a detailed description of how I harvested sunflower seeds one year, but cursory search hasn't turned it up.

...here's a different post I made that is less detailed:
https://www.helpfulgardener.com/forum/vi ... 99#p153299
...here's another one:
https://www.helpfulgardener.com/forum/vi ... 524#p84524

(I'm referring you to these posts since I wrote them when the details were fresher in my mind than now. This year's sunflower seeds are not ready to harvest yet. )

[imafan26]

Wait until the seed heads dry. The seeds are probably not ready yet. If you have cardinals or other birds around you may have to cover the heads to keep them from eating the seeds. A big paper bag or plastic bag works. If you use plastic you need to open it up if it gets steamy or mold will grow. The sunflower is a composite ray flower. I think inside the head of the flower there are thousands of tiny yellow flowers. Each one is attached to a single seed. Not every one of them will be pollinated and they do need to be pollinated. The duds will float when you do a float test and when you remove the seeds you can feel that they are empty inside.

P.S. I wasn't following this thread in the beginning, but even if your ground was hard, you only needed to use a fork to loosen it and maybe a little topsoil on top to plant the seeds. Sunflowers have large roots and between the roots opening up the space and watering, the sunflowers actually would help to loosen up the soil. They don't need much in the way of fertilizer anyway, just lots of space. My sunflower roots will go out pretty far so I plant them 3-4 ft from each other. I like mammoh for the seeds but for the show I prefer the multi-headed Chianti and Lemon Queen. They are a little shorter, but will put out flowers over a 4-6 week period. With mammoths there is a lot of anticipation but the flower barely lasts 10 days. It takes another month or so for the seed head to dry. You will be able to tell because you can rub the center of the head which will come off easily and see the plump seed pods.

[zanthal]

Thanks for the expert responses.

I planted these very late in the season, they only sprouted in the middle of August. It looks like they have quite a bit of time to go before drying out on their own as an annual does.

The overall growth of these appears to be a little stunted, they're only about 7 feet and don't appear to be getting any taller.

I dug about 2 foot x 5 foot trenches, two of them, and tried to sprout two plants in each. Only one in each trench actually grew well (the others wilted shortly after sprouting first leaves), and because of the position, each of them are certainly having roots that are a bit too close to some very hard soil.

I suspect that it is causing some of the height problems, but, it's a layman's guess.