posted 8 years ago
Yes you can, do some degree. Radishes mature very fast, like 21 to 28 days. Garlic is slow. You can absolutely sow radish seeds in between your garlic, more than once. Both those varieties don't have much vegetative growth above ground to shade each other out. Similar examples are beets, leeks, carrots, parsnips. All of those can be companion planted successfully as long as decent space is provided between each variety. Also those aforementioned won't compete very heavily for the available water in the soil. Growing anything too densely results in small produce.
Getting into tomatoes with potatoes, I personally would advise against it. Both those need full sun, and lots of it. The tomatoes (especially indeterminate varieties) will rapidly outgrow the potatoes shading them out, and the roots below ground start going far and wide and will compete for water and one will choke out the other (likely the tomato will win). You will end up with mediocre results. We like to garden to achieve great results with beautiful, delicious, nutrient dense food which puts a smile on our face and provides great satisfaction for our labors involved.
Here's an example of the amount of room I give my tomato plants. I grow in raised beds. Many of them are 4x8 foot, 1 foot deep. I will plant four tomato plants in one 4x8 raised bed. In april, it sure does look like I'm leaving a lot of unused space. I can grow quick maturing veggies (like radishes) in that unused soil in between my tomatoes. But, those tomatoes grow rapidly, and in July, my indeterminate tomato varieties are 6 feet tall, and have started to flop over the top of the tomato cage. By August they've made it back to the ground and are on their way across the ground. They have completely shaded the entire 4x8 raised bed, and drink the water out of that soil like nobody's business. In a perfect world, I would get an inch of rain, steadily over a few hours, every 3 days to keep the soil moist. That never happens so I irrigate every third day.
I am new to growing strawberries, this is my first year. I have them in their own designated raised bed. Everything I've read about growing strawberries is that they need their own space. They are aggressive and will take over. A friend of mine has been growing strawberries for a number of years and said something to the effect of "once you plant them you'll never get rid of them".
I hope this is helpful! Good luck!
"Study books and observe nature; if they do not agree, throw away the books." ~ William A. Albrecht