well a 1/4 acre is a nice sized food plot
a food plot can be any size, the smaller , well , you have to worry about them eating it faster than it can grow, but it will still work to draw deer to it, just like a pile of corn,
when corn is gone they still look for it there,
what and how big , is really up to you, and your soil
and what will grow best there as is
best plans are to look NOW that leaves are full on tree's and see how much sun light that field gets
next would be to go and take some sil in a bunch of spots in the field
and mix it all together and have a soil test done on it(cost about 10 bucks for a soil test)
this is one of the most important parts of a food plot
as it will tell you what your soil type is and what the PH is
pending WHO does the testing, many places will even recommend a seed for your soil type
IF not NOT
the soil PH will for sure tell you what/how big you can afford to go
90% of all food plot seeds will grow SOME in poor soil
but to get a good long lasting plot, you really want to get the Ph up to 6-6.5 or so
so a soil test will tell you how much or little lime it needs to get there, plus it if you tell them what seed you want to plant, how much fertilizer is needed
sounds a little confusing, but its really simple
your budget will then tell you how big, based on the soils needs
for a cheaper first plot, you can skip brand name seeds
most country feed stores in rural area's sell seeds by the Lb, like clover, rape, chicory, turnips, and the likes
for feed plots, summer time food, and spring, Clover is a great plot, it will last for 6-7 yrs or more if taken care of, but it looses its draw as frosts come, so its not the best hunting plot
feeds like Brasicia's, turnips, Rape, winter hardy oats, make for better hunting plots, as they come into there prime as frosts hits, and stand taller once snow falls, making easier and more attractive plants in hunting season till there gonein Jan feb or ?? pending how much you plant

the honest rule of thumb is this, plant a plot the size your budget allows, and do it right, add corect lime, and correct fertilizer, and seed amounts
a smaller plot planted well, will out grow a half assed one
something to think about
if you have any farmers in your area, right now is a slower time of yr, and many will for a reasonable fee, come and spray your site with round up, disc it, and even plant it
old rule , you never know till you ask
a farmer with a tractor can do a 1/4 acre site pretty fast, couple hrs to disc and plant at most
need a week or so after applying the round up
Cheap Forage rape seeds would be a good fall planting, need about 5 lbs, which at my local Agway would be avout 15 bucks in seed cost, ( a 50 lb bag is 60 bucks and will plant about 7 acres)
add in say 150 lbs of 10-10-10(about 45 bucks) and thats maybe high, on average its about 300 lbs an acre, so at just a 1/4 acre, you can maybe get away with less, again your soil sample will tell you this info!
a half a gallon of round up, about 10 bucks, and what ever is needed in lime, if you have a bulk delevery guy about, and the field is open to be driven on, its about 40 bucks a ton spread, ON average a ton of lime will raise your PH one point(many claim a 1,000 lbs will, but not in my experience, lime really needs time to work in to change PH, and most bulk spread lime is of lower quality in lime)
that's about a 100 bucks in seed/fert/lime
minus getting somone to spray it down and then turn it over /Disc it, price on thsi will depend on your local farmers, and how grown up the field is(does it need to be brush hogged or just disked)
add in another 150 bucks, and your at about 250 bucks for a good hunting fall plot! a ballpark figure
again your budget will say if this is high or not, can you can cut back as needed
exactly when you plant
this will be decided on two things, one, all seeds have a growth rate, like a 90 day seed or a 45 day seed, and so on
meaning you want to plant the seed so it will reach mature size before your normal frost dates in the area it will be planted
I have seen Brassicia's with as low as 38 days, and as high as 90 + days
so when you plant is by seed timing, and well when you actually have the time to plant!
trust me, over the yrs I missed my window to plant due to getting busy in life, and planted weeks later than planned
still worked out OK, not as great as it maybe should have been, but still worked to draw deer all hunting season!