A gardener has 1000 plants. He wants to plant these in such a way that the number of rows and the number of columns remain same. Find the minimum number of plants he needs morefor this?

I'm assuming that you mean, by "the number of rows and the number of columns remain same" that "there will be an equal number of rows and columns."
If so, then I will help you.

But, first things first. Please read the rules. This is obviously a homework question, regardless of where you posted it.
Your title to give you an answer is a no-go. We are here to help, not do the work for you.

Now, on to the actual problem.
Go find a multiplication table. Find the square values. You want to find the VERY FIRST SQUARE into the thousands. The number squared will be the number of columns/rows the farmer has. The square number will be 1XXX where the X's are whatever the square makes them to be. Then, you subtract 1000 from that number to get your answer.

For example. A farmer has 50 plants, but same scenario.

The FIRST square that is greater than or equal to fifty is 64, or 8. 64 - 50 = 14, so in the case of 50 plants the answer is 14. Now, do the same thing, but with 1000.

I'll solve the problem of HelpinHere in another way, if you don't mind HH ;)

Ok, the gardener has 50 plants. With that, he can have plants in each row and column. However, you cannot have a fraction of a plant. So, if he decided to make the same number of plants in each column and row, he would have taken 7 plants, with (50 - 7^2) = 1 plant left out. Since you are required to know how much more plants does he need to have, so that none is left out, you'll take 8 plants in each column.

So, 8^2 = 64. What he needs is (64 - 50) = 14.

Here, you can also see the number of 'left out' plants, which was a similar problem to the previous problem you posted in another thread.

Hope it helped! :)

Please make sure that you read the rules for posting on AMHD. It is not a place to get your homework questions answered. You will receive help, but shouldn't have other people do your work for you. How else are you going to learn?