Beginner's Question

[B]i am new to yoga. i’ve been practicing, seriously, since september. my hamstrings are really tight, so i have a hard time getting into an appropriate downward dog. are there any suggestions of poses that i could do to help lengthen my downward dog pose?

also, i have awful posture. are there any poses or exercises that you suggest to help strengthen my lower back and shoulders into being in a healthier position?[/B]

I’m not a teacher but I think “appropriate” pose is the one that you can comfortably do without strain and risk of injury. The ideal may be the most perfect V shape, but forcing yourself to do it with tight hamstrings and after 3 months of practice is not appropriate at all (in general forcing yourself into the pose is dangerous - you may end up with injury for months and even years). I suggest you to ask the teacher to correct your downward dog and just stick with it. Accept where you are and give yourself some time. And every month you will go deeper and deeper into the pose.

If you want to strengthen yourself faster - maybe consider doing some practice in the morning?

Ahhh the dreaded tight hamstrings. This is very common with a lot of people, myself included. There are many schools of thought on this one, some might even advise you to keep your knees bent to create length in the spine, which is very important in down dog. Other styles believe that keeping the legs straight is of vital importance to create circulation in the back of the knees. In this case I would stay on the toes in down dog, and perhaps make small movements of bringing your heels down to the ground. All the while keeping the spine straight and extend through the sides of the body. It will come, but be patient with yourself and most importantly if you have a regular teacher perhaps take a moment after class and ask for suggestions.
Good luck and enjoy the journey!

One, absolutely ask the person whom you have chosen to impart the practice to you. Otherwise the potential teacher-student relationship has been stifled AND you’ll never know if your teacher is any good:-)

Use supta padnagusthasana as part of a larger practice AND have a skilled teacher show you how to do it properly.

Finally, to clarify downward facing dog (for you based on your inquiry)…it is not only important to straighten the leg bones in the pose, it IS the pose. It is not a matter fo whether a (uh) student should bend the knees. It is a matter of whether THIS student should bend the knees. When the hamstrings are tight and the instruction to that student is to straighten the legs (only) then the spine would have to be rounded in the pose as the pelvis must tip back (posterior) in that student to meet the instruction.