PLANT CARE

Spring is one of the most exciting times of year for gardeners across Ontario. The days get longer, the weather warms up, and it’s finally time to refresh your planters, garden beds, porches, and outdoor spaces. But beautiful gardens don’t stop at planting day — they need continued care throughout the summer to stay healthy, full of colour.

At Arnolds Greenhouses, we’ve been helping local families grow something beautiful for generations. Whether you’re planting annuals, perennials, vegetables, herbs, shrubs or tropicals, these tips will help your garden thrive from spring right through late summer.

1. Wait for the Right Weather Before Planting

Ontario spring weather can be unpredictable. Cool nights and late frost can damage tender plants, so always watch the forecast before planting outdoors permanently.

Warm-loving plants like petunias, begonias, tomatoes, peppers, and tropicals prefer consistently mild overnight temperatures.

Tip: If a cold snap hits, cover plants or move containers to a protected area overnight.

2. Start With Fresh, Quality Soil

Healthy soil creates healthy plants. Use fresh potting soil for containers each season and refresh garden beds with compost or enriched garden soil.

Good soil helps with:

• Root development

• Moisture retention

• Drainage

• Stronger blooms and harvests

3. Water Smarter as Temperatures Rise

Spring watering is different from summer watering. As the weather heats up, plants dry faster and need more consistent moisture.

Spring:

Water when soil begins to dry.

Summer:

Water deeply and more often, especially during heat waves.

Containers and hanging baskets may need daily watering in peak summer heat.  

Best Tip: Water early in the morning and if able use weight of container/basket to gauge moisture levels.

4. Fertilize Plants Regularly Through the Summer

Plants use up nutrients quickly once they begin actively growing and blooming. Continued feeding through summer helps keep flowers full.

For Flowers:

Use water soluble fertilizer ever 1–2 weeks or as directed on label.

For Vegetables:

Use steady organic feeding during fruiting season.

For Hanging Baskets:

Frequent feeding keeps baskets lush and vibrant.

Consistent feeding = better colour, fuller plants, and longer-lasting performance.  Always follow specific manufacturer recommendations.

5. Deadhead and Trim Often

One of the easiest summer care habits is regular maintenance.

Remove:

• Spent flowers

• Yellow leaves

• Leggy growth

• Broken stems

This encourages fresh blooms, improves airflow, and keeps plants looking tidy.

Great plants to deadhead regularly:​

• Geraniums

• Ivy Geraniums

• Marigolds

• Dahlias

6. Protect Plants During Heat Waves

Hot Ontario summers can stress plants quickly.

Signs of heat stress:

• Wilting mid-day

• Crispy leaf edges

• Drooping baskets

• Dry containers

What To Do:

• Water deeply early morning

• Move containers to part shade if possible

• Mulch garden beds to retain moisture

• Avoid fertilizing during extreme heat days

7. Keep an Eye Out for Pests & Disease

Warm weather can bring aphids, mildew, beetles, and other common garden problems.

Check plants weekly:

• Under leaves

• New growth

• Discoloured spots

• Chewed leaves

Early treatment is always easiest. Healthy plants with proper spacing and airflow are naturally more resilient.

8. Mid-Summer Refreshes Make a Big Difference

By July or August, some plants need a little reset.

Try:

• Trimming overgrown baskets back slightly

• Replacing tired annuals

• Adding fresh soil to containers

• Fertilizing again

• Replanting herbs or lettuce

A quick refresh can make your garden look brand new again.

9. Continue Harvesting Vegetables & Herbs Often

The more you harvest many vegetables and herbs, the more they continue producing.

Pick regularly:

• Basil

• Parsley

• Lettuce

• Beans

• Cucumbers

• Tomatoes when ripe

Frequent harvesting keeps plants productive and healthy.

10. Plan for Late Summer & Fall Beauty

Strong summer care sets you up for an even better late season garden. Continue watering, feeding, and maintaining your plants so they stay beautiful into September and beyond.

Late summer is also a great time to add fresh perennials, ornamental grasses, and fall colour.