Mary, Mary, quite contrary, how do your children grow? With silver bells and tantrum spells, and blankies always in tow.

Mary, Mary, meet SeedlingsGroup, a team of child development experts and psychologists who understand that kids don’t come with planting instructions.

These pros offer advice on everything from thumb sucking and time-outs to imaginary friends, as well as caregiver training. Choose a one-on-one session at your home, office, or by phone, or connect with neighborhood parents whose children are within three months of yours.

From sibling rivalry to sleep issues, they clue you in on what to expect socially, emotionally, physically, and cognitively at each age and stage.

Adding a little reason to your nursery rhyme.

SeedlingsGroup (212-966-7273 or seedlingsgroup.com).

REGISTER
Big City Moms Super Pass Deal
What: DailyCandy Kids readers get $20 off passes to the biggest baby shower in town.
Why: Big bellies are big deals.
When: Deal valid thru Aug. 28. Limited availability. Event, Oct. 6, 6:30-9:30 p.m.
Where: American Girl Place, 609 Fifth Ave., at 49th St. R.S.V.P. to events@bigcitymoms.com or 917-488-8542.

PLAY
Arthur Ashe Kids’ Day
What: The US Open begins with tennis clinics, skills challenges, games, music, and special guests.
Why: Get in the swing of things.
When: Sat. Games and clinics, 9:30 a.m.-1 p.m.
Where: USTA Billie Jean King National Tennis Center, Flushing Meadows Corona Park, Main St. to Corona Ave. to 111th St., Flushing. Admission is free for games and clinics.

EXPLORE
Gone Fishin’
What: Sail the New York Harbor aboard a 19th-century schooner and trawl the waters for cool creatures.
Why: It’s reel fun.
When: Sat., noon-3 p.m.
Where: South Street Seaport Museum, 12 Fulton St., at Pier 16. Reserve at 212-748-8786 or online at reservations@southstseaport.org.