Protecting Your Garden

Hail

Hail is common in summer, especially along the Front Range and Eastern Plains. Use hail cloth or shade cloth on hoops or frames, keep old sheets or buckets handy for quick cover, and plant a few backups.

Frost

Watch forecasts in late spring and early fall. Cover tender plants in the evening with frost cloth (floating row cover), sheets or buckets, and remove covers the next day. Plastic touching leaves offers little protection.

Wind

Strong winds dry and break plants. Windbreaks such as fences, hedges or temporary screens help, as do sturdy stakes and cages.

Pests

Common issues include aphids, flea beetles, cabbage worms, squash bugs, grasshoppers and spider mites (which thrive in hot, dry weather).
Inspect plants often, handpick where possible and use row covers to exclude insects.
Identify the problem first. CSU PlantTalk and your county Extension office can help with diagnosis.

For aphids on indoor seedlings and house plants, see Aphids in Your Indoor Garden.

Wildlife

Deer, rabbits, voles and squirrels are frequent visitors. Fencing works best: deer generally need tall fencing (around 8 feet), while rabbit fencing should be buried a few inches to discourage digging. Repellents give mixed, short-term results.

Season extension

Row covers

Lightweight fabric adds a few degrees of frost protection and blocks insects.

Cold frames

Boxes with clear lids for hardening off seedlings and growing greens in spring and fall. Vent on sunny days.

Low tunnels

Hoops covered with fabric or plastic extend spring and fall harvests of cool-season crops.

Wall-of-water

Water-filled plant protectors help get tomatoes off to an early start.

Indoor pests

The guidance above is aimed at outdoor gardens. Seedlings and other plants grown indoors can still get insects, even if they never go outside. Aphids are a common problem on indoor plants and in seed-starting setups.

Aphids in Your Indoor Garden

Aphids often cluster on tender new growth and on the undersides of leaves. Act early so a small infestation does not spread through a seed-starting shelf or grow tent.

Isolate and treat plants

Move infested plants away from healthy ones.
Spray aphids off with lukewarm water, including the undersides of leaves and the stems.
Follow with insecticidal soap or neem oil every 5–7 days for 2–3 weeks, because new aphids keep hatching.
A simple homemade spray is 1 teaspoon of mild dish soap per quart of water. Test it on one leaf first and wait a day to check for damage before spraying the whole plant.
Cut off badly infested leaves and bag them; do not compost them.

Clean the grow area

Remove pots, trays, saucers, tools and supports from the area.
Vacuum shelves, the floor, windowsills and corners, then empty the vacuum outdoors so pests are not left in the room.
Wipe shelves, grow lights and tent walls with warm soapy water, then with 1 part bleach to 9 parts water or with 70% rubbing alcohol. Keep bleach off plants.
Scrub empty pots and trays in the bleach mix, rinse and let them dry.
Discard fallen leaves and used potting mix. Do not reuse soil from infested plants.
Wash or replace fabric pots and capillary mats.

Prevent a return

Hang yellow sticky traps to catch winged aphids and to help you notice a new outbreak.
Check the undersides of leaves twice a week.
Quarantine new plants for about two weeks before placing them with your other plants.
Go easy on nitrogen fertilizer; soft, lush growth attracts aphids.
Keep air moving with a small fan.
Watch for ants, which farm aphids for honeydew and can protect them.