Lawn seed for shade

I am wanting to try and seed an area under a massive Lime tree. Obviously the area is very shady and dry but want to give it a go. Once established, grass does grow under the tree as it overhangs the neighbouring field and grass seems to grow reasonably well that side.
My question is I've seen grass seed advertised for shady areas. Is this seed really any better than you bog standard mix or just the advertising boys finding a good excuse to remove more money from the back pocket?
I was also wondering if there is any way to lessen the chances of the seed being washed away pre germination if it rains heavily. The tree is now in leaf and when it rains there seem to be channels of water created on the ground under the tree. I would have seeded prior to the tree coming into leaf but my neighbouring farmer told me grass needs the soil to be at least 5 0C to get good germination so have left it till now. Thanks.

 

Hi Silu,
I would say the most important thing to remember when considering shaded/dry areas is that you must get moisture to the affected area, not many thing will grow without water, (how long can you go without a drink) it's just the same for plants.
Can you cut back some of the branches to let more light into the area, this would help a lot.
The tree roots are the culprit here, soaking-up most of the moisture and goodness from the soil leaving your grass to struggle on with little water and food, so if you want to have grass under your tree, you have to play your part by providing that extra water and light.
You could use a seed that is tolerant to drought and infertile soil, you could get this type of seed from your local garden center or seed merchant.
The hard soil around the base of the tree will have to be broken down by digging with a garden fork or rotavator then leveled our and fertilized ready for seeding.
When the new grass does start to grow I suggest you let it grow a little longer say between 25/30mm this will help in the morning when the dew is on the longer blades of grass giving the grass plants more moisture.
The soil temperature under trees is usually a lot less than in open areas of your lawn if the sunlight cannot reach it, so the grass plants will be a lot weaker and will require more attention, so keep this grass as long as possible.
You may also have to re-seed this area one or twice a year to maintain the level of grass you require.
Hope this helps.

 

Hello Mr Green ! Good to have an ex green keeper on our side Problem lawns must be our number one subject this time of year .

 

Thank you @ Mr Green. I'm beginning to think I should invest in some astro turf! There is no way I could trim back the branches. This tree is massive being well over 100 years old. The power company had to bring in professional tree surgeons to lop bits off it a few years ago. They wanted to slaughter it by taking 20 ft off it. I politely pointed out the tree was there a long time before they stuck their power lines up, that concentrated their minds on perhaps just doing a little pruning! I can get Snowdrops Aconites and Daffodils to grow under her but am doubtful as to whether there will be enough moisture to support grass. It doesn't help the ground I want/ed to seed is on a slope so drains like a sieve. Thanks @JWK. I think I'll buy a smallish box of shady grass seed and give it a go. No doubt it will rain soon after and the whole lot will end up flowing onto my newly created herbaceous border only to then sprout!
The photo shows the "offending" tree or part of it anyway. I have created a new herbaceous border and consequently the area around the Lime is now part of the garden while before it was a bit of a waste land