What I have learned about growing tomatoes
To say that I’m an expert gardener would be an extraordinary stretching of the truth; capable, yes, expert, not even close. While I tend to focus on what crops fail outright, or produce lower-than-desired yields, my neighbors and some of the folks I know online seem to be impressed with my results.
One of the crops I have grown each season since I started gardening has been tomatoes. As fickle as tomatoes can be, I seem to have consistently produced decent-or-better yields. In this post I would like to share what I have found to work, and not work, with growing tomatoes. The following is based on my own experimentation, and observations made of neighbors and friends.
This is the number one thing I notice other new gardeners mess up. It’s common enough to where I have vocally lamented the placement of tomato plants in a neighbor’s yard while walking the dog. I have also heard the complaints of friends, living in San Francisco, or somewhere equally overcast and foggy, complain about their weak tomato plants.
Tomatoes need an absurd amount of sunlight. I genuinely don’t think there is such a thing as “too much sun” for tomatoes.
The location I have chosen for my tomatoes receives sunlight from dawn until dusk, which means at the high point of the summer the plants will be receiving more than 14 hours of sunshine.
Delicious sunshine which they turn into delicious tomato.
I think, without any scientific data to back this assertion up, that if your location doesn’t guarantee 10+ hours of direct sunlight a day, tomatoes probably aren’t suitable for that location.
Assuming you do get 10+ hours, the next subject becomes very important.
When I first started gardening, I was fortunate enough to have absolutely garbage soil in my backyard. This forced me to “build it from scratch”, so I purchased many cubic feet of planting soil and manure. I still vividly recall that first season, the big, obviously a little slow, guy who worked at the garden supply store giggling as he loaded bags of manure into the back of my nice VW.
As time has gone on, I have learned so much more about soil and soil health. I fancy myself an organic farmer, not because I have an aversion to chemicals and chemistry, but because I have a fondness for bugs and biology.
Removing the tomato plants at the end of this 2017 season, I was absolutely astonished with how strong and dense the root systems were for the plants. Most certainly the strongest plants I have grown to date, with the most biologically active soil I have worked with to date.
Soil health, primitively speaking, boils down to three areas:
Planting soil by itself is not sufficient. One mistake I have noticed some folks make, will be buying some of that potting soil mix, plopping some tomato starts into it, and hoping for the best. Setting aside what I think of potting soil mixes (they suck) for a moment, planting soils provide some of the basic ingredients for success but are inert.
Good soil must be alive.
One of the mistakes I made early this season was just mixing manure into the soil. Putting manure into the soil isn’t enough, good compost is necessary.
Compost provides the biology your plants need to be successful.
What I tried in the 2017 was layering roughly 2-3 inches of compost over the top of the soil partway through the season. The plants looked undernourished, which is subjective to say the least, but they simply looked weak and had little branches and leaves. I demand bushiness from my tomatoes!
The compost seemed to really help kickstart the ecosystem in the garden box, and the tomato plants subsequently started to grow stronger more rapidly than they had previously.
I would estimate that for my tomato bed there is probably 1/2 cubic yard of “planting soil”, with 3-4 cubic feet of chicken manure, and approximately 5-6 cubic feet of compost layered over the top mid-season.
A lesson learned from the 2016 season in Santa Rosa was that the tops of the soil will cook during the harsh mid-day summer sun. While those 14 hours of sun were helping the plants, the tops of the soil crusted and dried out the soil very rapidly.
One of the things I learned recently about healthy and alive soil is that it retains water much better than “planting mix” does by itself. Inert soil acts like a dirty sieve for water to pass through, whereas alive soil behaves much more like a sponge, soaking up the water. This in turn makes it much more available for the plants.
What I did this season was layer straw mulch over every inch of exposed soil for every single bed, not just tomatoes. This practice combined with the addition of plenty of compost made for beds which provided adequate moisture to the tomatoes as they grew.
Last season I lost a number of tomatoes to blossom-end rot which can be caused by poor soil nutrition and/or the water demands of the plant not being met.
This year I didn’t see a single tomato with blossom-end rot.
One side benefit I noticed about the straw mulch is that it allowed a very active insect ecosystem to develop. I recall a number of times when I caught birds hopping through my beds, grabbing a delicious cricket or pill bug to eat. If you cannot see the life in your soil, it’s probably not “alive” enough, and needs some help!
A lesson I learned mid-way through this season is that soil pH is important. It’s not necessarily be-all-end-all for soil health, but it is a good approximate measure of whether the soil is acidic enough for the plants to properly access the nutrients they need like Calcium, Magnesium, Phosphorus, and Nitrogen.
This year, I purchased a meter (~$40) which tells me the soil pH, moisture level, and temperature, and immediately started testing. I was shocked to find out how far off almost every single one of my beds was from a “good” pH level. I spread some agriculture dolomite (limestone basically) along with my application of compost, which brought the pH back into “good” range within a week or so.
Setting aside any of the fancy tools you can buy, the number one thing I recommend looking for in your soil is whether there are insects. If there aren’t bugs in your soil, then there probably aren’t the little critters that bugs eat, and there aren’t the bacteria which the little critters eat. And if those bacteria aren’t there, there’s nothing working symbiotically with your tomatoes to help them grow.
Good soil is alive.
I grow my tomatoes in the classic tomato cages, which works fairly well. I do not however pay much attention to how they grow in those cages. During the growth phase I will guide them up-and-out as necessary, but not much past that.
I have never bothered pruning “suckers” from plants, but have read that some people see good results with it. I largely try to ensure that the vines are always supported and that any dead leaves are pruned immediately to allow other leaves to receive sunlight.
My tomato plants look messy, which frankly, I’m okay with. I want them getting as much of that delicious sunlight as they can get!
One thing I learned in the 2017 season is how much the weather can affect the productivity of tomatoes. The biggest challenge this year has been dealing with the heat and aggressive sun.
Due some exceptionally hot days this summer, I had a number of tomatoes develop thicker skins than I would like them to have. From my research, the best way I can defend against this in the future is with the use of shade cloth for the high points of the day to help reduce the temperature of the tomatoes themselves.
We’ll see how this goes next year, but it’s worth keeping in mind that tomatoes won’t “automatically” be delicious, there may be some week-to-week changes and management you need to perform to addresss the changing weather in your area.
The tips above are anecdotal at best. Take them with a grain of salt. For best success in your location, I strongly recommend keeping a log in a notebook of conditions, changes you make, and harvest over time. Referring back to this log at the beginning of the following season will help your plants improve with each successive year.
If there’s one thing you take to heart however, let it be this: good soil is alive.