I got this article from the net... hope this helps..
Lawn Care for a Year: A Monthly Maintenance Schedule for Ottawa
March (snowmelt)
・ Don't walk on soggy cold lawns
・ Remove debris from lawn
・ Inspect for dead patches and determine the cause (insect, disease, salt or mechanical)
・ Inspect for bare and thin areas
・ Sharpen mower blades
April
・ Lightly rake to break up snow mould and to remove loose thatch
・ Apply gypsum to yards in areas where pets have damaged the lawn
・ In salt-damaged areas, aerate, apply gypsum or lime and water deeply in the early morning to flush away the salt
・ Reseed dead patches and over-seed poor areas with a grass seed mix that is suited to the sunlight conditions for each area
・ Perennial rye and fescue grasses are more tolerant of salt than Kentucky bluegrass
・ Consider alternative ground covers and/or different landscaping to prevent future problems
・ Apply corn gluten meal, a natural pre-emergent herbicide if you haven't overseeded.
May
・ Aerate compacted areas of the lawn
・ Remove thatch if it is ½ cm, (¼" or pencil width) in depth
・ Topdress the lawn with organic material, such as compost, or with screened topdressing soil mix.
・ Spot seed and over-seed if you haven't already done so
・ Maintain the lawn at a mowing height of 7-8 cms (3"), leave clippings on the lawn, cut less than 1/3 of blade height each time.
・ Mow when grass is dry
・ Water deeply 2.5 cm (1") every 7-10 days if necessary, in the early morning
・ Fertilizers are not necessary especially if the lawn is treated with corn gluten meal, topdressed, or the clippings are left on the lawn after mowing. If fertilizing, use a balanced fertilizer
・ Hand pull weeds
・ Corn gluten meal reduces weeds and can be applied until the end of May. CGM is also a source of Nitrogen fertilizer. Do not use on areas seeded with grass seed
June
・ As grass growth slows, reduce mowing frequency
・ Monitor and treat for: heat stress, insects and diseases
・ If hot and dry, water the lawn about ½ cm (¼"-1/8"), every few days during the hottest part of the day to reduce heat stress
・ Hand pull weeds
・ Apply the summer treatment of corn gluten meal if needed
July
・ Maintain the lawn at a mowing height of 7-8 cms (3 inches)
・ Monitor and treat for: heat stress, insects and diseases
・ Fertilize with a balanced slow release or organic fertilizer (optional)
・ Water 0.5cm (¼"-1/8"), every few days or let the lawn go dormant (turn brown), don't cut until it recovers after a rain
・ Cut only when necessary
・ Hand pull weeds
・ Sharpen mower blades
August
・ As in July, allow grass to go dormant
・ Water deeply in the early morning, 2.5 cm (1 inch) every 7-10 days if a dormant lawn is not acceptable
・ Hand pull weeds
・ Monitor and treat for insects and diseases
・ Maintain mowing height at 7-8 cms
September
・ The fall is the best time to dethatch, aerate and topdress the lawn
・ Over-seed and re-seed weak patches
・ Water deeply in the early morning, 2.5cm (1 inch) every 7-10 days if there is no rain
・ Monitor and treat for insects and diseases
・ Apply a fertilizer low in Nitrogen and higher in Phosphate and Potassium to increase winter hardiness (optional)
・ Hand pull weeds
・ Apply corn gluten meal if not putting down grass seed
October
・ Monitor and treat for insects and diseases
・ Chop fallen leaves with mower and leave up to 0.5cm mulch, compost the remainder if insect and disease free
・ Service lawnmower and sharpen blades
・ Plan to minimize salt damage this winter by applying gypsum to the areas of the lawn normally affected
・ Hand pull weeds
・ Apply corn gluten meal in late October if grass seed was used in September
