Growing Tomatoes in Summer Heat: Five Mistakes to Avoid
Everybody grows tomatoes and a fair few of us lose them to the heat, and it is nearly always the same handful of things going wrong rather than anything exotic. I have made most of these myself, some of them more than once, so this is the short list of what actually kills a summer tomato crop here.
1. Watering that comes and goes
Tomatoes want a deep drink on a regular rhythm, because that is what pushes the roots down instead of leaving them sitting near the surface. The two ways people get it wrong are watering a bit every day, which keeps the roots lazy, and drowning the bed, which rots them. Push a finger into the soil before you turn the tap on. You want it damp all the way down and never soggy.
Inconsistent watering is also what splits the fruit and what brings on blossom end rot, so the plant tells you fairly quickly when you have got this one wrong.
2. Planting into tired soil
Tomatoes are greedy. They want soil with plenty in it and they want water to move through it rather than sit, so a compacted bed that has already grown something hungry will give you a small plant and not much fruit. Compost or aged manure through the bed before you plant is the whole fix, and it is a lot easier than trying to feed your way out of it in January.
3. Not staking them properly, and not doing it early
A tomato plant gets heavy and it gets heavy fast, and once a stem snaps or the fruit is lying on the dirt you are into broken plants and rot. Stakes or a cage go in when the plant does, because putting a stake through the root ball of an established plant does more harm than the fall would have.
4. Skipping the mulch
Summer here will pull the water straight back out of an uncovered bed. A good thick layer of mulch around the base holds that moisture in and keeps the soil temperature steadier, and it keeps the weeds off at the same time. Straw and sugar cane both work well and both break down into the bed afterwards, which is a second job for no extra effort.
5. Assuming they can take any amount of sun
Tomatoes love sun right up until they do not. On the really savage days the fruit gets sunscald, which is a pale leathery patch on the shoulder of the tomato, and the plant stops setting fruit altogether above about 35 degrees. Shade cloth over the top through the worst of the afternoon fixes it, and a taller plant on the western side does a similar job if you plan for it.
What to do with all that
Nobody starts out knowing any of this, and I certainly did not. Get the watering rhythm and the mulch right first, because those two carry most of the result, and the rest of it is tidying up around the edges.
Shop related products
- D.T. Brown Tomato Grosse Lisse Seed. The old reliable, and it handles our heat better than most.
- D.T. Brown Tomato Red Cherry Seed. Cherries keep setting fruit when the big ones sulk.
- Manutec Tomato Tablets 20g. Calcium at planting, which is the blossom end rot insurance.
- Brunnings Potash Power 2.5kg. Potash is what pushes flower and fruit rather than more leaf.
- Martins Organic Sugar Cane Bale 11kg. My usual mulch around the base of the plants.
- Brunnings Garden Compost with Seaweed 25L. Through the bed before anything goes in.
Did you know we also stock garden stakes and plant ties in the shop, along with shade cloth for the worst of the afternoon sun. They are not listed on the website, so give us a ring on (08) 8536 4333 to check what is on the shelf.
Seed, mulch and the feeding gear are all in the garden centre, and if your plants are doing something odd, bring me a photo and we will work out which of these five it is. Drop them in the comments below as well if you have a trick of your own.
More from the garden
- 5 Easy to grow tomato varieties for beginners
- 3 Easy to Grow Summer Vegetables for Beginners
- Summer Watering Tips to Keep Your Veggie Garden Thriving
Cheers, Candeece. I have staked a tomato after it fell over more times than I will admit to in writing.
