Ask the gardener: in the context of climate change, now is the best time to plant grass seeds

What to do this week Trees use nutrients from your soil to produce leaves, which each fall fall to the ground and decompose in the ground. It is nature’s perfect recycling. But we break this cycle and deplete our soil when we collect and pack our leaves to take away. Why are we doing this? Because we have lawns instead of forest floors, and whole leaves can choke lawns. A less wasteful job is to use a “mulching mower” to break up the leaves where they fall and allow the shards to disappear into the grass as a natural fertilizer. It works when you mow frequently. But if the leaf litter is thicker than one or two deep or overlaps the paving, we rake it or blow it into a corner of the yard and then lay it down to mow it into small pieces. Then we rake the pieces into a small pile to compost them for a year. The following fall, the leaf pieces decayed to a stage called “leaf mould”. It is the best mulch there is because it does not contain weed seeds and is very nutritious, like an organic health food for gardens. You can also make leaf piles of whole leaves, but in this case they will take several years to turn and will need to be enclosed or weighted down so they don’t blow away. Wooded areas can be good places to dump these leaves and let them decompose.

Q When is the best time to plant grass seed? I heard it was spring or fall. If fall is the answer, when is the best time?

JM, Hansen

A. Now through the end of October is the best time of year to plant, but check first that your municipality will let you water because once sown, your grass seed should stay lightly but consistently moist until it germinates, which takes about 10 days. If the seeds dry out before then, they may die and you will have to start over. Many people seed lawns in the spring, but with increasing summer droughts and heat linked to global warming, followed by increasingly mild winters, fall planting seems like the best option. April is my second choice.

Q I have six river birches in the yard, and on half of them the leaves are turning yellow and falling off. Is it normal in times of drought for this species to defoliate early? I water around the trunk and drip lines a few times a week. There are still green leaves throughout the tree, especially on the tops. Is it temporary or are the trees doomed?

AD, Plymouth

A. Some trees lose their leaves early in drought. And with rain levels several centimeters lower than normal for the year, we are still in a period of drought. Do not fertilize the trees, as this stresses them by forcing growth and makes them more thirsty. But you can still help your trees survive by watering them as long as they have leaves on them (and your city allows it). Once all the leaves fall, the trees go dormant and there’s nothing you can do but wait and see if they come back next spring. Mature leaf trees need 30 to 40 gallons per month. But new trees planted less than three years ago need that much water per week. Don’t forget to water the trees on the municipal streets in front of your house, especially if the poor live on a “hell strip” (surrounded by sidewalk).

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