Wednesday, May 8, 2013

10 things you need to know to grow fruits and veggies in flower pots

Strawberries growing at my terrace

Not everybody has a garden (for sure I don't), but that doesn't mean we have to forget about growing our own veggies or fruits. Of course not all the fruits are going to be appropriate to grow on flower pots, but there's a wide variety of them we can plant at our terrace, balcony, or even on the window (strawberries, cherry tomatoes, all the varieties of cooking herbs, lettuce, etc), and that if we take a little bit of care, we'll be able to have our own little kitchen garden too. Here's a list of 10 things you should keep in mind if you decide to have a kitchen garden on your terrace.

  1. Roots are made to grow under the soil, where the temperature is fresh even when it's very hot in Summer. However, when they grow in flower pots, the temperature can get really high, which can damage the roots of your plants. To avoid that, it's always better to use clay pots rather than plastic ones. Still, if you're using plastic pots, you can put the pot inside a bigger, empty pot, in that way the empty one around will isolate the other one from the high temperatures of Summer. It's also good to elevate the pots a little from the ground, specially if the terrace gets a lot of hours of sunlight (you can do that elevating the pots on pieces of wood, for instance).

  2. A few weeks after the plants and veggies are in the pot, the roots are going to reach the limit of the space and won't be able to extend anymore, making it impossible for them to go hunt for the nutrients they need to live (see points 4, 5 and 6). This happens way more often in pots than in an open garden: on first place because the soil is very limited and is not renovated, and secondly because every time we water it, we're dragging nutrients away.

  3. The soil around the plants has to be wet, but not soaked (never let it get dry, it really damages the plant and production will really go down). It also has to be really oxygenated, that's why it's important that you stir the soil once a week (if you don't the first layer is going to get hard, making it impossible for the roots to absorb the water and the nutrients properly), this will keep the roots fresh and oxygenated.

  4. Keep in mind that you'll eat the fruits/veggies or plants in the pot, so take care with the nutrients you put on the soil, because the plant will absorb them. That's why you should use natural, organic nutrients, not only is better for your health, but you'll also be able to reuse materials instead of throwing them. There's a lot written about this and if you look at the internet you'll find a bunch of websites talking about different ways to make compost, I'll talk about two of them (see next two points).

  5. Egg shells are very rich in calcium (almost 93% of it is calcium), and calcium is one of the minerals that  veggies and fruits need for biological process like cellular division. To be able to use egg shells to feed the plant, you'll have to dry them in the oven and then grind them. This is important, because if you put them not grinded in the earth, not only the roots are not going to absorb them properly, they could also rot and damage the soil and the plant.

  6. Something else that we can use to feed the earth is coffee grounds. Coffee grounds contain nitrogen, phosphates, potassium, and sugar, which makes them a very rich nutrient for our kitchen garden in pots. Once you've made your coffee, instead of throwing the grounds, spread it in the earth, making sure you don't pile it all around the same area. It's important that you do it right before making the coffee, or it could mold and damage the plant. If you're not going to use the grounds right after making the coffee, you can use the oven to dry it and avoid the molding.

  7. Make a hole under the pot, if there's none. I know that almost everybody does it, but it's important that we don't forget about that. In that way the plant can get rid of the excess of water easily, and, at the same time, it will help the roots oxygenate. 

  8. Veggies that grow in flower pots are weaker than veggies than grown in gardens, specially when we talk about species that make a lot of fruits, like cherry tomatoes. In that case is very important to keep the plant clean, remove all the leaves that are not in good condition, and also the fruits that are not growing well. Otherwise the plant is going to spend all its strenght to fix that damaged part, making it impossible to grow other fruits in good condition. It's always better to get a limited quantity of fruits than are in good condition, rather than a lot of them bit all poor. At the same time, avoid leaving fruits on the plant when they're already in condition to be eaten, otherwise we're making the plant do an extra effort to keep those alive.

  9. It's very possible that our veggies and fruits attract the insects, it happens. Again, remember what we said in point number 4: you'll eat that, so don't apply any kind of toxic product to kill the plagues. Instead, use organic homemade insecticides that won't damage the plant and won't damage your health either. For example: grind 6 clovers of garlic into half  a little of water, then filter it. Spray it on the plant, it will help fight the most common plagues, such as louses or the red spider.

  10. Don't put together two plants that are of the same family, because they both need the same nutrients from the earth and their roots will expand in the same way, which means that they'll damage each other. For instance, if you have a large pot don't put in it both tomatoes and eggplants, because even if they're different vegetables they both belong to the family of the solanaceae. Instead, a good combination would be to mix tomatoes and lettuces, for instance, because they both belong to different families.


  1. This is all great advice! My grandmother (a fantastic gardener) always uses coffee grounds and eggshells on her plants, not only the edible ones. She also uses soapy water to gently wash the leaves of plants that are victim of spiders —I suppose this doesn't work on all plants.

    I've been a clueless gardener until recently, now I'm comfortable with container gardening, which is all that's allowed to me as an apartment dweller...

    1. Ooh, I didn't know about the soapy water! That can come in as handy as well! :)