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?

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

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!

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.

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