you can google images for plant costumes, here's what I found:
(http://t1.gstatic.com/images?q=tbn:ANd9GcRaK17ZNTLwQwf2cMQ07RtuvoxGpMtxHT6WeHBaaBN0cYgfdH4v-A)(http://t1.gstatic.com/images?q=tbn:ANd9GcS0Jn9iJ08aPN78Rc8zvV2OoVcGDW-4owk-9r0Lasfmi1jNmOAKfA)(http://1.bp.blogspot.com/_8kLBhU4jzU4/TNzjSwIL1rI/AAAAAAAAAOc/ZW6-lK3Pitk/s1600/CPK%2BComparison%2B001.JPG)(http://t1.gstatic.com/images?q=tbn:ANd9GcRL-qBi6wW6XRXk2RGQZVqkYSuJDTvOFqgtAXfp88pC6AgiQSjS)(http://t2.gstatic.com/images?q=tbn:ANd9GcQym4dRL-tIoyKX3n13jh8-esFFe9a3GMOqdjL1duP5OnfLIcKxJ-BESDgO)(http://t2.gstatic.com/images?q=tbn:ANd9GcRelp-N_d0jYdfl8XIVZcLsTpv8niL2bBMJqwcCAg8WW5_dids_sw)
image from http://www.comicsfornerds.net (http://www.comicsfornerds.net/), www.mascotcostumemall.com (http://www.mascotcostumemall.com/),schmidthedz.blogspot.com,blog.zeer.com,smartmascotcostume.com, jejeizahfaye.com, http://thefairygardenerquiltstoo.blogspot.com (http://thefairygardenerquiltstoo.blogspot.com/)
For the skeleton frame of the seed, you can use a native"duyan". make holes for head and arms, cover with cloth and make a plant sprout hat
The pea costume illustrated on the 3rd picture is easy. Make 3 balls covered with felt cloth and sew it on the front.
Nutrition month headdress and costumes were discussed on the previous page:
http://www.smartparenting.com.ph/parentchat/index.php/topic,20731.msg396587.html#msg396587 (http://www.smartparenting.com.ph/parentchat/index.php/topic,20731.msg396587.html#msg396587)
And here are more ideas I found on google images.
(http://t2.gstatic.com/images?q=tbn:ANd9GcS9piX55Q2HY6rpGRW3xAZzpeEeJRPMVh9Jl_EGW14ws6c8NARo)(http://t1.gstatic.com/images?q=tbn:ANd9GcTfKJQvaVekuPNacShw-KjdU8l_zks0SLUlTaws585UcEkjCnh3bA)(http://t3.gstatic.com/images?q=tbn:ANd9GcR5nHRkDtRtWl-OAx54vVgr8uV-it6Hqrsn3uiVVenpkOCWzdcm)(http://2.bp.blogspot.com/_S4L6AhIXYXk/SHSsFOUjUXI/AAAAAAAADR8/m3cufpWT-vs/s400/C13.jpg)(http://www.kidzlist.com/images/blog/20114515-1206-bigstock_Kid_with_salad_and_tomato_hat__15442769.jpg)(http://img.designswan.com/2011/11/hair/1.jpg)(http://paperclipsandplaypens.com/images/020110_04.jpg)
images from http://lacycreations.com (http://lacycreations.com), sundrania.com, smashedpeasandcarrots.blogspot.com, http://mysoulfulthoughts.blogspot.com (http://mysoulfulthoughts.blogspot.com), image from http://www.kidzlist.com (http://www.kidzlist.com), http://img.designswan.com (http://img.designswan.com), image from http://paperclipsandplaypens.com/ (http://paperclipsandplaypens.com/)