Wednesday, September 23, 2009

Tomatoes Three Ways

I'm going to spend the next week or so running seedlings around ... they go inside when it rains and at night. They go outside when it's sunny. But there's still plenty of stuff to do in the meantime. So now I guess it's finally time to lay out the Grand Tomato Plan (henceforth, GTP).

I'm doing four varieties this year, and none are rated for disease or pest resistance. If you missed it in the earlier post, I'm growing Marvel Stripe (an heirloom, bicolor tomato), Giant Belgium (a huge beefsteak), Homestead 24 (bred for hot weather), and a yellow tomato called Azoychka. If you're doing a more popular variety (e.g., Celebrity, Better Boy, cherry, or Roma), don't worry. All the following still applies.

Because this blog is experimental, I'm going to be using three methods to grow my tomatoes:
  • The ground (Homestead 24)
  • Big containers (Marvel Stripe and Giant Belgium)
  • EarthBox (Azoychka)
Each of these requires a slightly different approach, so over the next three days, I'm going to take it one by one and talk about how to set up each different grow. I'll start with growing in the ground.

I keep saying that South Florida has challenging soil. Here's why. Although there are a few different soil types around South Florida, for the most part, our native soil was derived from oolitic limestone, which runs like a rocky spine down the Florida peninsula. Combined with sand, rock, muck and marl in various degrees, this means our soil 1) is very alkaline (the pH is above seven) and 2) does not transport nutrients and oxygen well to the plants' root zone. Additionally, parasitic bugs called nematodes are ubiquitous.

All of this is bad for tomatoes.

So if you're growing in the ground, it's imperative to improve the soil before you plant. Here's why:
  1. It will lower the pH. Don't underestimate the importance of soil pH. Tomatoes prefer a pH of about 6.0 to 6.5. Our soil ranges from 7.5 to higher. Neutral is 7.0. This can dramatically affect the availability of nutrients and reduce your yield.
  2. It will add organic matter. Tomatoes are heavy feeders, and they absolutely thrive in an environment that's loaded with nutrients—hence, lots of decaying organic material.
  3. It will fend off nematodes. Nematodes don't like organic matter because it's acidic (a pH lower than seven). By amending your soil, you'll reduce the nematode micropopulation to a manageable level, so you can still get a good harvest before the plant succumbs.
But here's where it gets a little tricky ... there are as many opinions on how to improve soil as there are people growing tomatoes. And each back yard can be different, so what works for me might not work for you. Nevertheless, there are a few soil amendments that you'll see crop up again and again. I'll list them here, and then I'll tell you which ones I'm using.
  • Sphagnum peat moss. This is the base ingredient for most bagged soilless potting mixes. It's derived from peat bogs in Canada and elsewhere. It's rich in organic material, but it's too acidic for excellent tomatoes and doesn't contain adequate nutrients. You can buy it in big blocks from most garden centers. Lambert's is the brand I use.
  • Pine bark fines. Pine bark fines are used to provide structure to soil. They are small pieces of pine that are partially composted. Pine bark fines decompose slower than sphagnum moss, so they don't compact as quickly and strangle the plant's roots. However, pine bark fines are hard to find and tend to be expensive.
  • Compost. There are many kinds of compost: composted cow manure, composted chicken manure, forest products, and of course, you can make your own from a simple compost pile. Compost is rich in nutrients and is great stuff. However, if you plan on using added fertilizer (which most people do), it's not strictly necessary.
  • Perlite. Perlite is a natural mineral that is sterile, non-absorbent and lightweight. It's used to increase the aeration of soil, thus making more oxygen available to the plant (which is crucial). Perlite is often the second ingredient in most bagged potting mixes.
  • Lime. Ah, the Great Lime Question. There are two kinds of lime commonly sold for horticultural purposes: hydrated and dolomitic. I'll handle this in a different post, but for now, lime is used to raise the pH of sphagnum moss and provide calcium and magnesium to tomatoes. And there is a difference between the two, so don't use them interchangeably.
  • Organic fertilizers. There are many additives people use to add nutrients to their base soil. These include blood meal (nitrogen), bone meal (calcium and phosphorous), worm castings, Epsom salt (magnesium), even powdered milk (calcium again) and lots of others. (If you're getting the idea that tomatoes like calcium, you'd be right.)
This next part is like cooking a big stew. You throw ingredients into the pot and wait for a bit, except in this case the "pot" is either a big hole in the ground or a raised bed. Personally, I plan to dig a big hole, add a 50 lb. bag of composted cow manure (I use Black Cow, available in most garden centers), add about the same amount sphagnum peat moss, mix in a gallon or two of perlite, add two cupfuls of dolomitic lime to adjust the pH, mix in some bone and blood meal, and then mulch it over well. This basic mix is pH adjusted, well aerated, rich in organic material, and provides nitrogen, calcium and phosphorous. This doesn't mean, however, that I won't be using fertilizer. I'll still fertilize the tomatoes, but I'll use less.

Because it's best to amend your soil a week or two before you actually plant to let things simmer, I'll probably handle it this weekend. Photos to come ...

One note about using regular bagged potting mix. I see lots of people buying tomato plants and a bag of potting soil. This is fine. Miracle-Gro potting soil and others are often amended with slow-release fertilizer and perlite already, so they do some of the work for you. My only caution here is to avoid bagged potting mixes with added water crystals. These crystals hold too much water near the root zone, and you risk ruining your fruit. So if you want to make life a bit easier on yourself and just pick up a bag of potting mix, make sure to look for a brand that doesn't contain water crystals. Personally, I like Fafard, but there are lots of others out there.

And that's it!

Up tomorrow: Container Culture


  1. cool! I can't wait.

  2. Let me share to the steps on how to grow tomatoes - Sowing and Plantingtomato. This is my way, I hope you'll like it.

    Tomatoes need warmth and light. Earlier crops can be sown in a heated greenhouse keeping a minimum night temperature of approximately 13C(55F). Sow seeds in late December, plant out into their final positions by late February or early March. Harvesting should begin in May or June.

    This is an expensive way to learn how to grow tomatoes and is time consuming in terms of energy input i.e. gas or electricity, insulation, and monitoring the ventilation. But... if your Mr or Mrs Moneybags then give it a go.

    For gardeners like you and me, knowing how to grow tomatoes at minimum cost is advisable - so we let nature provide all the light and heat that we need. Sow tomato seed in an unheated greenhouse in early April for planting out in May.

    You can bring this forward by three weeks by raising your seedlings inside an electric propagating frame either built into your greenhouse or one that you can purchase from a garden centre or DIY store.

    I built mine (photo on left) about 20 years ago and I find it invaluable for raising seedlings and for rooting cuttings at a relatively low running cost.

    Another way of providing tomato plants is to purchase seedling plants from a reputable supplier. This is very cheap to do if you only need a few... but it is important that you trust where you are getting them as you may introduce disease. If in doubt ask about their origin.