Sunflowers Concerns: Current pot sizes and future home, the lawn

11 years ago

I started my first sunflower last August with seeds in a paper cup that thrived pretty well and I changed the pots 2 times (I have documented this in my plant journal). A couple of weeks ago I started new seeds in the paper towel method and moved them to paper cups. But after watching many Youtube videos I have a concern for their initial development as I not only used smaller paper cups compared to what I saw in the videos, but I also planted the seeds from the paper towel with not much soil as evident in my journals and the photo. My goal is to transfer all 14 of these to the lawn outside (photo attached) without any re-potting in between but directly from these paper cups after they grow a little more to be able to withstand the transplantation shock and pests.

I don't want to invest much into 14 of larger pots as currently my only options would be cutting plastic water bottles half way through and moving the seedlings from the paper cups to those OR, collecting more paper cups (perhaps a bit larger in size) and transplanting the seedlings with enough soil so the soil is just a little more than half an inch below and rim of the cup. Also, I have not created any drain holes as I did the first time I grew sunflowers, the reason being nutrients drainage and the reason that paper cups get soggy if the outer wax is cut and the drain holes end up closing anyways and the sogginess have attracted white paper bugs. Further more I am prone to use paper cups as it is easier to cut them on the side with scissors making removing the plant with soil easier. Any suggestions on re-potting would be great which Is my primary concern at the moment.

Moving on to the lawn, as I said my plan is to plant these sunflowers in the lawn but there seems to be grass outside which is not any special kind just weed. My plan is to divide the lawn into two lengthier halves and so there is walking space on the left side and sunflowers on the right in 7 rows, next to the boundary wall. I read that sunflowers plant when matured enough can out-compete the grass for nutrients however I have sprinkled some old sunflower seeds cut in half to prevent germination, but for the purpose that I read about online that sunflower seed shells are toxic to grass. Am I good to go ahead and replant in my lawn in the coming weeks?

Here is a link that might be useful: Plants Journals documenting previous sunflowers and current seedlings

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Comments (4)

SouthCountryGuy Zone 4b-5 SE BC
11 years ago
IMHE, sunflowers do not do as well when transplanted. They send down a deep tap root that does not like to be disturbed. I have found that each time they are transplanted or potted up it stunts growth. They are best sowed where they are intended to grow. I am not saying they will not grow it is just that the plants do not get as big as those sown where they are to grow.

I have not heard about the shells being toxic to grass but the roots supposedly have an allelochemical that can inhibit growth of some plants. What it would do to grass I could not comment on. These allelochemicals are said to be able to remain in the soil for several years. So if the shells or other parts of the plant also contain the same allelopaths you may have to wait several years for them to disappear.

Good luck and would love to see a picture when they are growing.

SCG
rhizo_1 (North AL) zone 7
11 years ago
SCG, sunflowers are allelopathic but the hulls and seeds pack the most wallop, I think. Allopathic chemicals don't linger very long in the soil, once the offending plants or parts have been removed. All in all, the whole plant can cause problems for SOME plants. Some, including assorted species of grasses, show no effect whatsoever.

Invisi, I cannot imagine the success of growing a plant in a paper cup! How do you intend to water it properly? If you decide to go with something sturdier, I strongly urge you to poke a few holes in the bottom. You WANT the excess water to drain through.

But, I would follow SCG's good advice and sow the seeds directly into the soil where you want them to grow. I'm always pulling sunflower seedlings up from under the bird feeders!
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Naveed Iqbal
Original Author
11 years ago
Gentlemen, thank you for you responses but please do look at the photos of my first sunflower here https://www.plantvillage.com/gardens/82?locale=en . I sprouted them in the same paper cup, transplanted two times and I was more worried than happy they didn't grow any taller, at least being a first timer. I believe I can improvise a little differently following what I learnt from previous time but needed a few tips so as to take care of anything that might come in the way of successful sunflowers in the end.

As for how I water them, I observed pretty well from last time how much I need to water. I have been using spray gun and have been carefully watering each paper cup and only letting the sun evaporate the water. I have used a mixture of sand and manure and I have observed that sand tends to dry off faster than manure so I am also carefully not to let the seedlings have to push through hard soil. I would say they are thriving pretty well in the paper cups just concerned if I should give them sort of a bridge or a buffer of larger containers in between before finally moving them out to the lawn.
SouthCountryGuy Zone 4b-5 SE BC
11 years ago
rhizo_1, Thanks for the info on the seeds and hulls. I am very careful where I plant sunflowers as I am unsure of how long the chemicals hang on.

Invis Transplanting sunflowers stunts (slows) growth dramatically, at least in my experience. A couple years ago I started several variety of sunflowers indoors 6 weeks prior to my planting out date. I planted these seedlings that were already about 30cm tall in the garden and about 30 cm away sowed a seed of the same variety. In 6 weeks ALL the plants from the seeds sown directly in the ground had outgrown the plants started in the ground. All the sunflowers that were started and transplanted ended up being about 2/3 the others size.

It is, again in my opinion, detrimental starting sunflowers in pots. I also believe each time you transplant them it has a negative impact on growth. IF I was to start them in pots again I would do so in large, deep pots so the tap root will not reach the bottom before you plant out. I would also be very careful when transplanting to ground to not disturb the roots in anyway.

Good luck

SCG