Understanding good greenhouse techniques encourages healthy plant growth and, as the growing season is well on its way, it would be a good time to reassess your plants’ performance to see if there are areas which can be tweaked for better results.

Consistent care and monitoring the plants’ growth contributes to good cultural practices. If you water erratically, plants may become stressed. Water earlier in the day rather than late, if possible, but if you need to water in the afternoon, try to water early enough to give the soil a chance to warm up and give the plants a chance to dry off.

Good sanitation is another area of concern. Any clutter that takes up space, absorbs light, or collects stagnant water will work against plant maintenance.

Insects and disease pathogens love to breed in stagnant water, so storing flats, pots and tools away from growing areas is a good habit to get into.

Bags of soil amendments, fertilizers and potting mixes should be stored in individual airtight and waterproof containers and kept away from children.

When removing old leaves and/or spent flowers, put them in the compost, don’t just leave them on the floor of the greenhouse. This will help maintain the floor of the greenhouse and keep it weed-free.

Cultivating between rows of plants is beneficial both to the plant and the roots. Simply take a hand-forked type garden tool and disturb or turn the soil. This also helps prevent green mould from forming on the soil which is caused by a combination of cold soil, cold water and lack of air circulation.

Hand-cultivate around the plants and possibly prune plants — especially tomato plants — around the soil level which could go a long way toward the prevention of fungi type of diseases.

Often I get asked about older leaves on tomato plants turning yellow. If the plant is otherwise green and healthy and mature, it could be simply that the older leaves are dying off and/or are not getting enough light because of the heavy foliage canopy above it.

On a large tomato plant, the lower leaves up to the first fruit cluster can be pruned off.

If, however, the overall plant is lighter green, leaning to yellow-green, the problem may be nitrogen deficiency. Plants use nitrogen in large amounts and if there is not enough, the plant uses it from the lower older leaves to support new growth. The solution is simply applying a balanced fertilizer containing sufficient quantities of nitrogen.

Another item to be aware of this time of the year is various greenhouse pests.

Inspect new plants as you bring them into the greenhouse. Walk through the greenhouse daily and inspect your plants looking for chewed leaves, creepy crawlies and anything that moves.

Fortunately, we have a limited number of insect pests which could change with climate change. For now, the biggest worry seems to be aphids.

Putting up insect traps such as a yellow sticky card will let you determine if you have any flying insects. Flying insects seem to be attracted to yellow.

By hanging a 5×7 piece of yellow card stock covered in honey, or any other sticky substance, you’ll soon find out if you have a pest problem.

By spending time in your greenhouse, and being aware of what is happening, you can prevent many of these problems from developing or getting out of control.